This case comes before the court en banc to review the substantial issue of the power of the Coast Guard to board and search American vessels on the high seas beyond the twelve-mile limit. A panel of this court held the boarding of an American shrimping vessel, the interrogation of its crew, and the search of the vessel unconstitutional. United States v. Warren, 550 F.2d 219 (5th Cir. 1977). We reverse.
A jury convicted the four defendants of conspiring to import marijuana into the United States, in violation of 21 U.S.C. § 963 (1976), and of transporting from the United States an amount of money in excess of $5,000 without filing the report required by 31 U.S.C. § 1101 (1970), in violation of 31 U.S.C. § 1058 (1970). Each defendant was sentenced to eighteen months imprisonment for the conspiracy to import marijuana and to six months for the monetary violation. The sentences of each defendant were to run concurrently.
The panel reversed the convictions of ' John Warren, Thomas Warren, and David DeFina. It affirmed the conviction of Des Schick. En banc review was granted, but only as to Thomas and John Warren. We reverse the panel’s decision as to the Warrens. The panel’s affirmance of Schick’s conviction and its reversal of DeFina’s conviction are left undisturbed.
I. Facts
The substance of this case is a conspiracy to import from Colombia into the United States approximately ten tons of marijuana. The Government’s chief witness was John Cruse, an unindicted coconspirator. He testified that Schick, a close friend, approached him in the early summer of 1974 and asked him to captain the shrimping vessel Stormy Seas to make the run. Cruse agreed, and subsequently he met with Thomas Warren at least twice (with Schick attending) to discuss the details of the venture.
A few weeks before the departure of the Stormy Seas for Colombia, Cruse, and Schick drove to John Warren’s residence in Miami and picked up a small boat belonging to John Warren. It was to have been used to unload the marijuana from the Stormy Seas upon return to the United States. A few days before departure, Cruse and Schick went to the Tallahassee apartment shared by Thomas Warren and DeFina, where they received from DeFina (Thomas Warren was not present) a trash compactor that was to have been used to compress the marijuana. The compactor and 300 plastic bags were placed on the Stormy Seas. On the eve of departure, DeFina provided a small boat that was also placed on board and was to have been used to load the marijuana in Colombia.
These preparations having been made, Cruse and Thomas Warren left Apalachicola, Florida, in the Stormy Seas on August 15, 1974. They sailed to Key West where they took on fuel and picked up John Warren, who was to serve as navigator. The following day they put to sea for Colombia.
In the early evening of August 19, the Coast Guard Cutter Steadfast sighted the Stormy Seas as she sailed southward between Haiti and Cuba in the Windward Passage. The Steadfast hailed the Stormy Seas and told her to prepare for boarding. At a point approximately 700 miles from the United States, the Stormy Seas received a party including three Coast Guard officers: Lt. Miller, who was in charge of the boarding party, Ensign Ryan, and First Class Quartermaster Tuck. Accompanying these officers were Special Agent Battell of the Drug Enforcement Agency and Agent Wallace of the Customs Service.
Lt. Miller introduced himself and the other members of the boarding party and asked to see the master of the vessel. John Cruse identified himself as the captain, and Lt. Miller asked for the ship’s enrollment papers. Cruse produced the papers, and Lt. Miller noted that they did not indicate that the Stormy Seas was bound for a foreign port. Following customary Coast Guard procedure, Agent Battell inquired whether any firearms were aboard, and Thomas Warren stated that there were. He led *1062Ensign Ryan and Agents Wallace and Bat-tell to the crew’s quarters where a .22 cali-bre and two .38 calibre pistols were produced. When the guns were brought forth, Agent Battell asked Thomas Warren why the guns were on board, and in his reply he stated that the purpose of the cruise was to speculate in land in South America. Record, vol. 2, at 80. According to the testimony of Agent Battell, during this conversation Thomas Warren evinced some confusion. Warren asked, “What’s this all about?” and remarked, “We are all in this together.” Id. at 214.
Agent Wallace and Ensign Ryan testified that they and Agent Battell made a “cursory search” of the Stormy Seas immediately after the guns were produced and transferred for identification to the Steadfast. Id. at 61-62, 229 (Wallace); Id. at 44 (Ryan).1 During this search a small amount of marijuana was discovered in Cruse’s cabin. According to Agent Wallace, this discovery “aroused my suspicion somewhat,” prompting him to make a more thorough, though unproductive, search of Cruse’s cabin. Id. at 61-62.2
Agent Wallace testified that after he had conducted this search, he questioned Cruse as to the nature of the trip. Cruse answered that the Warrens had chartered the Stormy Seas for fishing and diving. Id. at 62. John Warren also stated that the purpose of the cruise was fishing. Id. at 81. Agent Wallace had noted, however, the absence of any ice in the hold that could have been used to preserve the catch. Id. at 62. While examining the ice hold, he did see scuba gear, which, according to Lt. Miller, “was in pretty bad shape.” Id. at 19.
These circumstances, along with the conflicting stories of the Warrens and Cruse as to the nature of their trip, led Agent Wallace to suspect “the purpose of this trip was going to be to bring back narcotics.” Id. at 77. He reasoned that money for purchasing the narcotics might be on board. Id. Therefore, he asked Cruse and the Warrens, who were gathered on the fantail, whether they had any money on board. Thomas Warren answered that he had a “couple of thousand dollars.” Agent Wallace asked what he meant by that answer, and Thomas Warren replied, “maybe $5,000.” Agent Wallace asked whether he had more than that; the reply was, “maybe $7,000.” Agent Wallace then asked whether the money had been declared. Thomas Warren answered “no.” Id. at 39-40, 48-49, 63-64, 81, 207, 232.
Agent Wallace asked to see the money, and Thomas Warren led him, Agent Battell, and Ensign Ryan to the crew’s quarters. Warren lifted up the corner of a mattress and removed several envelopes, which he handed to Agent Wallace. While the mattress was raised, additional envelopes were exposed. Agent Wallace examined the envelopes handed him and realized that they contained more than $7,000. He advised Thomas Warren that there was a possible currency violation, and at this point Agent Battell read Warren the warnings required by Miranda v. Arizona, 384 U.S. 436, 86 S.Ct. 1602, 16 L.Ed.2d 694 (1966).
Additional envelopes and cash were removed from under the mattress. Later, envelopes containing cash were discovered in a briefcase. The total recovered was $41,500 and 46,800 Colombian pesos. Thomas Warren was led back to the fantail, where John Warren and Cruse were given their Miranda warnings and arrested.
Agent Wallace testified that after these events, he and Cruse, who had volunteered to assist, went to the hold to conduct a *1063search. While in the hold, Agent Wallace advised Cruse that he was “very possibly in some serious trouble with exporting money,” and asked, “Are you going for a coke run?” Cruse responded that they were not going for cocaine, but for “pot.” Record, vol. 2, at 237.3
The defendants were transferred to the Steadfast. Subsequently, an extensive inventory search was conducted by the Coast Guard, during which the trash compactor and plastic bags were discovered behind paneling in the aft hold. Additional evidence was found, including a letter to Thomas Warren from the Colombian consulate giving instructions for complying with Colombian customs, a legal pad of Thomas Warren listing equipment to be used to load and package the marijuana and referring to Colombian contacts, and Thomas Warren’s passport showing that he had visited Colombia just two weeks before the Stormy Seas set sail.
II. The Panel Opinion
The panel hearing the appeal in this case ruled that the warrantless search of the Stormy Seas violated the fourth amendment. This ruling was founded on two theories. First, the panel held that Agents Battell and Wallace were not authorized to assist the Coast Guard either in the questioning of those on board the Stormy Seas or in the search that ensued. The panel reasoned that any evidence adduced by the two agents was therefore unconstitutionally obtained. Second, the panel ruled that even the Coast Guard officers had no authority to extend their inquiry beyond that called for by a customary safety and documentation check. With all deference to the panel, we think that the Coast Guard had authority to stop and board the Stormy Seas and to question her passengers and captain and that the participation of Agents Battell and Wallace did not diminish this authority. We find the scope of the interrogation of the defendants while on board the Stormy Seas to be justified by the circumstances of this case.
The panel also concluded that Thomas Warren’s admission to Agent Battell that he had $7,000 was obtained in violation of the fifth and sixth amendments because Warren had not been read the Miranda warnings prior to this admission. Moreover, it was held that because this admission had been illegally obtained, it could not support the subsequent search of the Stormy Seas. Our analysis leads us to the conclusion that this statement was not obtained in violation of Miranda. Moreover, that the warnings were not given until after Thomas Warren produced the incriminating envelopes is of no constitutional moment because Miranda does not apply to the production of the physical evidence in this case. Since the actions of the Coast Guard and of Agents Battell and Wallace were within their authority and because Thomas Warren’s admission that he violated the reporting requirement was not gained in violation of Miranda, the evidence obtained from the Stormy Seas was properly admissible at trial.
The panel noted, but did not pass upon, the assignment of error by the Warrens that the district court improperly admitted into evidence a statement Thomas Warren made at the time of the defendants’ arrest. Thomas Warren, an attorney, had stated that he wished to represent his brother John and Cruse, and he advised them to remain silent. This statement was related at trial by Agent Battell on direct examination. Record, vol. 2, at 221. The Warrens assert that this testimony was an impermissible comment on their right to remain silent. Because we reverse the panel’s decision with respect to the Warrens, we reach this issue in our discussion below and find the admission of the statement not violative of the Warrens’ fifth amendment rights.
John Warren asserts two additional errors upon which the panel ruled. First, he claims that the trial court improperly denied his motion for severance after Thomas Warren’s statement, “We are all in this *1064together,” was elicited at trial during the direct examination of Agent Battell. The panel held that the admission of this statement violated Bruton v. United States, 391 U.S. 123, 88 S.Ct. 1620, 20 L.Ed.2d 476 (1968), which prohibits the introduction, in a joint trial, of a eodefendant’s confession incriminating the defendant, when the co-defendant refuses to take the stand. Since we find this statement properly admissible against John Warren as a statement by a coconspirator during and in furtherance of the conspiracy to import marijuana into the United States, Bruton does not bar its introduction at trial. Second, John Warren contends that the trial court violated Ped.R. Evid. 615 by allowing government witnesses to remain in the courtroom during the pretrial suppression hearing. The panel ruled that the judge erred in denying the defendants’ motion to exclude the witnesses. Although we agree that the district court erred, we do not think this error so prejudicial as to require the reversal of the Warrens’ convictions.
In our analysis below, we shall address these issues in the order presented. We note here several determinations of the panel that we believe to be sound. Both Thomas and John Warren objected to the admission of testimony by Agent Battell that defined the word “shirts,” which appeared in the letter from the Colombian Counsel’s office to Thomas Warren, to mean cocaine.. The passage containing the word is, “don’t forget to pick up my shirts from Ozzie.” The Warrens complained that the testimony was inadmissible because they had not been charged with any violation concerning cocaine. The panel concluded that the admission of the testimony was “harmless in light of the weight of the other evidence,” 550 F.2d at 226, and we agree. The panel also determined that a statement by the Government to the jury during rebuttal argument, “no one has given you . any reasonable explanation of why John Warren and Tommy Warren were on a shrimp boat 700 miles [at sea with the trash compactor, plastic bags, and money],” was not an impermissible comment on the defendants’ right to remain silent. Id. at 226 n.8, 227-28. We agree with this determination as well. See United States v. Dearden, 546 F.2d 622, 625-26 (5th Cir.), cert. denied, 434 U.S. 902, 98 S.Ct. 296, 54 L.Ed.2d 188 (1977); United States v. Hill, 508 F.2d 345, 347 (5th Cir.), cert. denied, 422 U.S. 1009, 95 S.Ct. 2633, 45 L.Ed.2d 672 (1975). Finally, the panel dismissed as without merit a contention by Thomas Warren that the trial judge made certain impermissible comments during the voir dire examination of prospective jurors. 550 F.2d at 226 n.7. We concur with the panel’s resolution of this issue.
III. Analysis
A. Authority for the Boarding of the Stormy Seas, the Interrogation, and the Search
Federal law authorizes the Coast Guard to
make inquiries, examinations, inspections, searches, seizures, and arrests upon the high seas and waters over which the United States has jurisdiction, for the prevention, detection, and suppression of violations of laws of the United States. For such purposes, commissioned, warrant, and petty officers may at any time go on board of any vessel subject to the jurisdiction, or to the operation of any law, of the United States, address inquiries to those on board, examine the ship’s documents and papers, and examine, inspect, and search the vessel and use all necessary force to compel compliance.
14 U.S.C. § 89(a) (1976). This law is constitutional, United States v. One 43 Foot Sailing Vessel, 538 F.2d 694 (5th Cir. 1976), and pursuant to its authority, the Coast Guard may apprehend and board any vessel of the American flag. This authority is plenary when exercised beyond the twelve-mile limit; 4 it need not be founded on any particu*1065larized suspicion. United States v. Odom, 526 F.2d 339, 341-42 (5th Cir. 1976); United States v. One 43 Foot Sailing Vessel, 405 F.Supp. 879, 882 (S.D.Fla.1975), aff’d, 538 F.2d 694 (5th Cir. 1976). The cases have recognized the power of the Coast Guard, having boarded a vessel of the American flag, to conduct documentation and safety inspections. United States v. Hillstrom, 533 F.2d 209, 210 (5th Cir. 1976), cert. denied, 429 U.S. 1038, 97 S.Ct. 734, 50 L.Ed.2d 749 (1977); Odom, 526 F.2d at 342. If, during the course of such an inspection, circumstances arise that generate probable cause to believe that a violation of United States law has occurred, the Coast Guard may conduct searches, seize evidence, and make arrests. Odom, 526 F.2d at 342.
The boarding, interrogation, and search in this case come within these principles. The Coast Guard officers and the agents boarded the Stormy Seas pursuant to the authority of section 89 to conduct a safety and documentation inspection and to look for obvious customs and narcotics violations. Record, vol. 2, at 74, 85-86. In the course of this inspection, the enrollment papers were examined, and they indicated that the Stormy Seas was destined for no foreign port. Thomas Warren, however, professed the purpose of the trip to be land investment in South America. Later, Cruse and John Warren stated that the Stormy Seas was chartered for fishing and diving, but no ice to preserve catch was aboard and the diving gear was apparently inoperative. According to the testimony of Agent Wallace, these circumstances led him to suspect that the Stormy Seas was on a narcotics run and motivated him to inquire as to how much money was on board. This inquiry elicited the admission by Thomas Warren that he possessed approximately $7,000 and that he had not registered it upon departure from the United States. Thomas Warren’s statement established an apparent violation of customs law, and a large amount of money was uncovered after he led members of the boarding party to the crew’s quarters. The defendants and Cruse were arrested, after which Cruse confessed that the Stormy Seas was on a “pot” run. The vessel was seized, and a search uncovered evidence confirming Cruse’s confession.
Each link in this chain of events, from boarding to inventory search, is legally sound. The boarding was lawful, and the scope of the interrogation was determined by well-founded suspicion. The currency was revealed after Thomas Warren admitted that he had not registered it, and the search that produced the evidence upon which the marijuana conspiracy convictions were based took place after the arrests and *1066after Cruse confessed that the Stormy Seas was on a “pot” run.5
Seeing the facts in this light, we think that this case is controlled by our holding in United States v. Odom, 526 F.2d 339 (5th Cir. 1976). In that case, the Coast Guard sighted an American vessel, the Mar-J-May, some 200 miles from the United States in the Yucatan Straits, between Cuba and Mexico. Apparently without prior suspicion that narcotics or customs law had been violated, the Coast Guard boarded the Mar-J-May to conduct a routine safety and documentation inspection. During the inspection, a Coast Guard officer noted that the fishing gear was “rusty and unused.” Id. at 341. The officer, wishing to examine the main-beam identification number located in the hold, was told that the hold was full of ice and that it would be difficult to see the number. After some consideration, the officer decided to open the hatch, and when he did, he saw only a small quantity of ice. He entered the hold and examined the identification number, and at this time he noticed several unmarked burlap bags in the aft of the hold. The bags were inspected, and approximately 6,000 pounds of marijuana were discovered.
The court held that section 89 authorized the boarding, regardless of whether “reasonable suspicion” that the contraband was on board existed. Id. at 341-42. Thus, the court found it unnecessary to determine whether a Coast Guard boarding beyond the twelve-mile limit is analogous to a roving border patrol, which, as established by the Supreme Court in United States v. Brignoni-Ponce, 422 U.S. 873, 95 S.Ct. 2574, 45 L.Ed.2d 607 (1975), may stop vehicles when there exists a “reasonable suspicion” that a violation of law has occurred. The court determined that the events that transpired before the bales of marijuana were examined “supported a finding of probable cause to search the hold of the ‘Mar-J-May.’ ” 526 F.2d at 342. The court noted that the fishing gear appeared to have been inoperative, that the captain of the Mar-J-May had been reluctant to open the hold and had falsely represented the hold to be full of ice, and that an “undetermined amount of burlap sacks [were seen] in the rear of the hold.” Id. The court concluded as follows:
To summarize, the initial boarding and administrative inspection made by the crew of the “Valiant” was permissible under 14 U.S.C. § 89. Further search was supported by probable cause after the facts mentioned above became evident to Chief Fieck. We therefore hold that the marijuana seized from the “Mar-J-May” was properly admitted in evidence, and that the district court correctly denied the motion to suppress.
Id.
Although we think Odom is directly on point here, the defendants contend that the facts of this case distinguish it from Odom. First, they argue that the participation of Agents Battell and Wallace in the events that took place on the Stormy Seas invalidated the boarding, interrogation, and search because the Coast Guard lacked authority to delegate its powers to the agents. Second, they urge that a customs regulation required the boarding of the Stormy Seas to have been founded upon probable cause. We find both of these contentions unpersuasive, and we take them up in order.
1. The Participation of the Agents
The Coast Guard is expressly authorized by statute to employ officers of federal *1067agencies in carrying out its duties. The statute, 14 U.S.C. § 141(b) (1976), provides in pertinent part, “The Coast Guard, with the consent of the head of the agency concerned, may avail itself of such officers and employees ... of any Federal agency . . .as may be helpful in the performance of its duties.” It is clear on the face of section 141(b) that Agents Battell and Wallace were authorized to assist the Coast Guard in carrying out its legitimate functions, provided that the “heads” of the Drug Enforcement Agency and Customs Service had given the required consent.
Although the record does not expressly indicate whether consent was given, we think it a fair inference that at least implied consent existed. Moreover, it is incumbent upon the party moving to suppress evidence to demonstrate a lack of authority for its acquisition. The defendants made no contention, either in the district court or on appeal, that consent was lacking.6 Even if the defendants had demonstrated that Agents Battell and Wallace were not authorized by section 141(b) to assist the Coast Guard in its actions in this case, that these actions were carried out jointly is sufficient to bring the agents under the aegis of the Coast Guard. See United States v. Bates, 526 F.2d 966 (5th Cir. 1976). We hold, therefore, that the participation by the agents in the boarding, interrogation, arrests, and seizures in this case does not invalidate those actions.
2. The Customs Regulation
The defendants press a more colorable argument upon us in their assertion that a regulation promulgated by the Treasury Department required the boarding party in this case to have premised its apprehension and boarding of the Stormy Seas upon the existence of probable cause. The regulation, 19 C.F.R. § 162.3 (1977), provides in pertinent part,
(a) General authority. A Customs officer, for the purpose of examining the manifest and other documents and papers and examining, inspecting and searching the vessel, may at any time go on board:
(2) Any American vessel on the high seas, when there is probable cause to believe that such vessel is violating or has violated the laws of the United States
Officers of the Coast Guard are deemed customs officers, and thus apparently subject to this regulation, by two provisions of title 14 of the United States Code.7
The first provision is 14 U.S.C. § 89(b) (1976), which provides,
*1068(b) The officers of the Coast Guard insofar as they are engaged, pursuant to the authority contained in this section, in enforcing any law of the United States shall:
(1) be deemed to be acting as agents of the particular executive department or independent establishment charged with the administration of the particular law; and
(2) be subject to all the rules and regulations promulgated by such department or independent establishment with respect to the enforcement of that law.
On its face, section 89(b) appears to subject Coast Guard officers to 19 C.F.R. § 162.3 when they are enforcing customs laws.8 The defendants argue, therefore, that 19 C.F.R. § 162.3 requires the Coast Guard to have had probable cause to believe that a customs violation had occurred or was occurring on board the Stormy Seas before the boarding could legally have taken place.
The argument under section 89(b) fails because of section 89(c), which states,
(c) The provisions of this section are in addition to .any powers conferred by law upon such officers, and not in limitation of any powers conferred by law upon such officers, or any other officers of the United States.
We think it clear that by enacting section 89(c), Congress intended to give the Coast Guard the broadest authority available under law. As we have noted, the Coast Guard is empowered under section 89(a) to seize and board vessels of the American flag on the high seas without probable cause or any other particularized suspicion. Therefore, the customs regulation cannot restrict the power of the Coast Guard in this case, at least as far as the regulation applies by virtue of section 89(b)(2).
The Warrens, however, proffer a second provision of title 14, 14 U.S.C. § 143 (1976). It provides,
Commissioned, warrant, and petty officers of the Coast Guard are deemed to be officers of the customs and when so acting shall, insofar as performance of the duties relating to customs laws are concerned, be subject to regulations issued by the Secretary of the Treasury governing officers of the customs.
They point out that section 143 contains no counterpart to section 89(c) that would mitigate the requirement of probable cause imposed by 19 C.F.R. § 162.3. Our analysis of the legislative histories of sections 143 and 89 leads us to the conclusion, however, that section 143 should not be read to impose limitations upon the powers of the Coast Guard when it boards American vessels beyond the twelve-mile limit.9
The original version of section 8910 was enacted in direct response to the Supreme Court decision in Maul v. United States, 274 U.S. 501, 47 S.Ct. 735, 71 L.Ed. 1171 (1927). See H.R.Rep.No.2452, 74th Cong., 2d Sess. 2 (1936). In that case, the Court held that the Coast Guard had authority to seize an American vessel thirty-four miles from shore. The vessel had become subject to forfeiture because she had undertaken a foreign voyage without being duly registered. The Court found that the Coast Guard’s authority derived from a statute empowering customs officers (and Coast Guard officers because they were deemed customs officers) to seize vessels that had *1069become subject to forfeiture “by virtue of any law respecting the revenue, as well without as within [the customs officers’] respective districts.” 274 U.S. at 505, 47 S.Ct. at 737. The Court construed the statute to provide for Coast Guard seizures beyond districts designated as customs enforcement areas, that is, beyond twelve miles from the coast.
As evidenced by the committee reports, e. g., H.R.Rep.No.2452, 74th Cong., 2d Sess. 2 (1936), Congress adopted and went beyond the holding of Maul to provide the Coast Guard with broad jurisdiction over American vessels. The reports echoed concern expressed by Justice Brandéis in a concurring opinion to Maul that the holding of the case, founded as it is upon the construction of a revenue enforcement statute, might be read to require express statutory authority for Coast Guard seizures for violations of laws other than those relating to revenue. Id. at 2-4; Maul, 274 U.S. at 512-31, 47 S.Ct. at 739-46 (Brandéis, J., concurring). Congress enacted the predecessor of section 89 to ratify the broad power of the Coast Guard to seize American vessels beyond the twelve-mile limit for the violation of any applicable law of the United States. As we shall demonstrate, section 143 is based upon different considerations.
Section 143 derives from two provisions of the Anti-Smuggling Act of 1935. Both provisions, like the current section, are definitional. Section 201 of the Act, Act of Aug. 5, 1935, Pub.L.No.238, § 201, 49 Stat. 521, includes within the term “officers of the customs,” any “commissioned, warrant, or petty officer of the Coast Guard.” Id. Section 401 merely reiterates, verbatim, section 201 of the Act. 49 Stat. at 529.11 Neither section, however, contains any language similar to that in 14 U.S.C. § 143 that subjects Coast Guard officers to customs regulations. Such language arose for the first time in section 143, which was enacted in 1949. Act of Aug. 4,1949, Pub.L.No.207, § 1, 63 Stat. 506. This is the version currently in effect.
Since section 143 is the direct descendant of the Anti-Smuggling Act of 1935, we think a discussion of the legislative history of that Act essential to the construction of the section. This history indicates that the predecessors of section 143 were not intended to affect the powers of the Coast Guard exercised beyond the primary jurisdiction of the Customs Service. In our opinion, this distinguishes section 143 from this case.
The Anti-Smuggling Act was occasioned by the failure of the repeal of prohibition to diminish substantially the smuggling of liquor into the United States. See Ficken, The 1935 Anti-Smuggling Act Applied to Hovering Narcotics Smugglers Beyond the Contiguous Zone: An Assessment Under International Law, 29 Miami L.Rev. 700, 708 (1975). A significant part of the smuggling trade was carried out by foreign vessels. Under then existing United States law, foreign vessels were immune from arrest beyond the twelve-mile limit notwithstanding treaties with several nations that allowed the seizure within one hour’s sailing distance from the coast of foreign vessels engaged in the smuggling of liquor. The treaty provisions were unavailable beyond twelve miles because the United States revenue law had not been extended beyond that limit. See id. at 707 n. 25.
Congress enacted the 1935 Anti-Smuggling Act to expand the force of internal law to the limits provided by the treaties. See H.R.Rep.No.868, 74th Cong., 1st Sess. 2, 4 (1935). The Act also greatly enlarged the authority of customs officers to board and search vessels and to seize contraband within the enforcement area established by the Act. See id. at 12. To remove any ambiguities as to the authority of Coast Guard officers to avail themselves of this broader authority, Congress enacted the definitional provisions of. the Act from which 14 U.S.C. § 143 derived.
*1070The history of section 143 indicates unequivocally that its precursors were not designed to affect the authority of the Coast Guard regarding American vessels sailing beyond areas in which foreign vessels were subject to customs regulation. The jurisdiction of the Coast Guard over American flag vessels beyond the twelve-mile limit had been established under the holdings of Maul and its companion case, United States v. Lee, 274 U.S. 559, 47 S.Ct. 746, 71 L.Ed. 1202 (1927). The same Congress that responded to Maul by enacting the precursor of section 89 also passed the Anti-Smuggling Act. We think the intent of Congress is clear: Congress meant that section 89 should define the authority of the Coast Guard over American vessels beyond the twelve-mile limit. That authority allows boardings without suspicion of illegality. Subsection c of section 89 interdicts any regulations that might impinge upon that authority. Therefore, we will not read section 143, which derives from an act designed to expand Coast Guard jurisdiction over foreign vessels, to limit the Coast Guard when acting pursuant to its powers under section 89 over American vessels beyond the twelve-mile limit. Accord, The Underwriter, 13 F.2d 433, 434 (2d Cir. 1926), aff’d sub nom. Maul v. United States, 274 U.S. 501, 47 S.Ct. 735, 71 L.Ed. 1171 (1927). The probable-cause-for-boarding requirement of 19 C.F.R. § 162.3 does not apply to the boarding in this case.
B. The Miranda Issue
The issue we must determine is whether the Miranda warnings that were given Thomas Warren immediately after he produced the first envelopes, which contained money in excess of $5,000, came too late. The panel was of the opinion that the warnings should have been given before Thomas Warren’s admission to Agent Wallace that he possessed more than $5,000. Apparently, the panel believed the defendants to be in custody at the time the questions concerning the amount of money each had on board were asked. Of course, it is the existence of a custodial atmosphere that invokes the necessity for the warnings. Miranda, 384 U.S. at 444, 86 S.Ct. at 1612; United States v. Carollo, 507 F.2d 50 (5th Cir. 1975), cert. denied, 423 U.S. 874, 96 S.Ct. 143, 46 L.Ed.2d 105 (1976).
The panel noted several circumstances that led it to the conclusion that the defendants were in custody at the time of the questioning. The defendants had gathered on the fantail of the Stormy Seas, their guns had been removed, the boarding party was armed, and the Steadfast stood by with three machine guns that could have been used to restrain the Stormy Seas. Under the special circumstances attending the boarding by the Coast Guard of a vessel on the high seas, we find that the restraint of the defendants in this case did not reach a level of custody that would require Miranda warnings at the time the questions concerning the money were asked.
It is essential at the outset to recognize the nature of the boarding and interrogation in this case. Every American flag vessel on the high seas is subject to Coast Guard boarding and inspection. See note 4 supra. Therefore, the coercive atmosphere that is the primal indicium of a custodial interrogation, see, e. g., Hoffa v. United States, 385 U.S. 293, 303-04, 87 S.Ct. 408, 414-15, 17 L.Ed.2d 374 (1966), is generally absent because such boardings are routine. This, of course, is not to say that such intrusions cannot be coercive, but the routine Coast Guard boarding and inspection of an American vessel on the high seas does not create a custodial situation. Cf. United States v. Thompson, 475 F.2d 1359, 1364 (5th Cir. 1973) (routine customs search does not require Miranda warnings). See also United States v. Jones, 543 F.2d 1171, 1173 (5th Cir. 1976), cert. denied, 430 U.S. 957, 97 S.Ct. 1604, 51 L.Ed.2d 807 (1977). Indeed, to hold otherwise would require the Coast Guard to read Miranda warnings to those on board every vessel it boarded.
We must, therefore, look beyond the routine boarding and interrogation in this case to determine when the warnings should have been given. This determination requires a case-by-case analysis. E. g., *1071Alberti v. Estelle, 524 F.2d 1265, 1266-67 (5th Cir. 1975), cert. denied, 426 U.S. 954, 96 S.Ct. 3181, 49 L.Ed.2d 1193 (1976). The Fifth Circuit employs a four-factor test to ascertain whether an interrogation occurred in a custodial context. These factors include: (1) whether probable cause to arrest had arisen, (2) whether the subjective intent of the officer conducting the interrogation was to hold the defendant, (3) whether the subjective belief of the defendant was that his freedom was significantly restricted, and (4) whether the investigation had focused on the defendant at the time of interrogation. United States v. Nash, 563 F.2d 1166, 1168 (5th Cir. 1977); Alberti v. Estelle; United States v. Carollo, 507 F.2d 50 (5th Cir. 1975), cert. denied, 423 U.S. 874, 96 S.Ct. 143, 46 L.Ed.2d 105 (1976); Brown v. Beto, 468 F.2d 1284 (5th Cir. 1972); United States v. Montos, 421 F.2d 215 (5th Cir.), cert. denied, 397 U.S. 1022, 90 S.Ct. 1262, 25 L.Ed.2d 532 (1970). Under these factors, we think it clear that a custodial situation did not exist at the time Agent Wallace asked Thomas Warren how much money he had.
Probable Cause. Admittedly, Agent Wallace testified that he suspected that the Stormy Seas was on a narcotics run. The enrollment papers had listed no foreign port as a destination, but Thomas Warren stated that the purpose of the cruise was to purchase land in Colombia. John Warren and Cruse stated that the Stormy Seas had been employed for fishing and diving, but no ice was on board and the diving equipment was in obvious disrepair. These circumstances, although clearly sufficient to warrant further inquiry, would not have supported an arrest. It was not until Thomas Warren admitted that he had failed to report the $7,000 he claimed to possess that probable cause to believe a crime had been committed arose.12 Indeed, the defendants agree. They argue that no probable cause to search the vessel or make arrests existed before Thomas Warren’s admission. Brief of Appellant John L. Warren, Jr. at 25-26 & n. 28; Brief of Appellant Thomas Warren at 14 & n. 9. See note 5 supra.
Subjective Intent of Officer. It is clear that the subjective intent of the boarding party was to restrict the freedom of the Stormy Seas. But, as we have noted, this alone does not render the interrogation coercive. The freedom of every vessel that is boarded by the Coast Guard is restricted to the extent that the vessel is not free to leave until the inspection is completed. If the intent-of-the-officer criterion is to have any meaning in the context of a Coast Guard boarding, then the officer must intend to go beyond the restrictions imposed by the customary and routine boarding and search. Although Agent Wallace testified that he made the inquiries because he suspected that the purpose of the trip was to procure narcotics, the record does not reflect that he intended to take Thomas Warren into custody at that point.
Subjective Belief of Defendants. The issue of the effect of a customary Coast Guard boarding upon the minds of those on board a vessel such as the Stormy Seas is essentially the obverse of the one just discussed. To the extent that the boarding and inspection are routine, the defendants *1072should not feel coerced. In this case, it is clear that the defendants contemplated a boarding because they had devised a cover story to be used in that event. See Record, vol. 2, at 290-91. Moreover, John Cruse testified that just after the Steadfast was sighted, he advised the Warrens that the stop would be for a safety inspection. The record contains the following colloquy:
[MR. WHITTEN, the prosecutor:] Was there any discussion between you and either Mr. John Warren or Mr. Tommy Warren after the Coast Guard cutter was sighted?
[JOHN CRUSE:] Just that there was a Coast Guard boat coming, and they asked me what they wanted, and I told him that they checked safety inspection, you know, life jackets, fire extinguishers.
Id. at 291. Thus, although the defendants apparently believed that they would not be free to continue their voyage until inspection had been completed, they had no reason to feel coerced because they expected nothing more than a routine safety inspection.
The relevant inquiry is whether Thomas Warren believed that at the time of the questioning, the boarding and interrogation had gone so far beyond the customary that he was imminently subject to arrest. We think that the record indicates, however, that Thomas Warren believed the enterprise to be viable at that time. The trial judge found that Warren’s responses were intended to corroborate his explanation that the cruise was undertaken to speculate in land in South America.13 Therefore, we find that the record supports a determination that Thomas Warren did not believe his freedom to be significantly infringed at the time of the questioning.
Focus of Investigation. Agent Wallace’s interrogation was merely investigatory until Thomas Warren admitted that he had not registered the money. It is only when the investigation shifts to the accusatory that it is sufficiently focused under this criterion. “Where the officers are merely trying to ascertain the facts to see if a federal crime has been committed, the accusatory stage has not yet begun.” Wakaksan v. United States, 367 F.2d 639 (8th Cir. 1966), cert. denied, 386 U.S. 994, 87 S.Ct. 1312, 18 L.Ed.2d 341 (1967). See generally Miranda, 384 U.S. at 444 n. 4, 86 S.Ct. at 1612; Escobedo v. Illinois, 378 U.S. 478, 84 S.Ct. 1758, 12 L.Ed.2d 977 (1964). Moreover, the rule in this circuit is that if none of the other factors are present, that the investigation is focused upon the defendant is insufficient to render the interrogation custodial. United States v. Corollo, 507 F.2d at 52-53. See also Alberti v. Estelle, 524 F.2d at 1267.
Our findings under these factors lead us to the conclusion that Thomas Warren was not due a reading of his rights at the time he answered the questions posited by Agent Wallace. The record indicates no further questioning until Thomas Warren produced the envelopes that contained money in excess of $5,000. At that time the warnings were given. It cannot be successfully contended that the production of these envelopes without prior warnings was viola-tive of Miranda, because Miranda does not apply to the production of physical evidence. See United States v. Moffett, 522 F.2d 1379, 1381 (5th Cir. 1975); United States v. Thompson, 475 F.2d 1359, 1364 (5th Cir. 1973). Therefore, the evidence derived from Thomas Warren’s admission that he had not reported the money was properly admissible at trial.
C. The Comment-on-Defendants’-Silence Issue
Agent Battell testified at trial that Thomas Warren advised John Warren and Cruse to remain silent after their arrest. We must determine whether the reception of this testimony requires reversal of the convictions in this case. We hold that it does not.
*1073The testimony in issue was elicited by the Government during direct examination. The trial transcript reveals the following dialogue:
[MR. WHITTEN:] Agent Battell, did there come a time when all three persons on board the STORMY SEAS were read their rights?
[AGENT BATTELL:] Yes, sir.
[MR. WHITTEN:] Was there any conversation thereafter w,ith persons on board?
[AGENT BATTELL:] Yes, sir, there was.
[MR. WHITTEN:] What was that?
[AGENT BATTELL:] John Warren- or, correction, Thomas Warren, stated, “I want to represent everybody,” and requested the other individuals we had in custody not to say anything.
Record, vol. 2, at 221. Defense counsel objected immediately, and there was no further testimony on the matter. Most significantly, Agent Battell did not relate John Warren’s reaction to the advice.
We think it manifest that the admission of this testimony did not constitute a comment on the exercise of the Warrens’ right to remain silent. It is only where the accused is amerced for having exercised his constitutional rights that error is committed. This premise is implicit in the fundamental prohibition set out by the Supreme Court,
it is impermissible to penalize an individual for exercising his Fifth Amendment privilege when he is under police custodial interrogation. The prosecution may not, therefore, use at trial the fact that he stood mute or claimed his privilege in the face of accusation.
Miranda v. Arizona, 384 U.S. 436, 468 n. 37, 86 S.Ct. 1602, 1625, 16 L.Ed.2d 694 (1966). All that the testimony indicated was that Thomas Warren advised his brother and Cruse not to say anything. The jury could not have known whether the advice was in fact heeded. The testimony does not imply that Thomas Warren himself chose to exercise his right; he merely admonished the others not to speak.
That it was not brought forth at trial that the defendants in fact “stood mute or claimed [their] privilege” distinguishes the cases that the defendants claim require reversal. They proffer our decision in Baker v. United States, 357 F.2d 11 (5th Cir. 1966). Baker held that it was reversible error to allow an FBI agent to testify that the defendant requested a lawyer and “made no further statement” when first questioned. Id. at 13. As we said, “to have proven that [the defendant] made no further statement was, we feel, as objectionable as it would have been to comment on a defendant exercising his Constitutional right hot to take the witness stand.” Id. at 13-14. In this case there was clearly absent any proof that the defendants made no further statements. The same considerations distinguish the other case the defendants present, Walker v. United States, 404 F.2d 900 (5th Cir. 1968). . In Walker, a Government witness testified that he asked the defendant, “Just how did you get my [stolen] credit cards?” Id. at 902, n. 1. The witness testified that the defendant responded, “I refuse to answer on the grounds it might incriminate me.” Id. We noted, “When an accused responds to a question, or even to an accusation, with an assertion of a claimed legal or constitutional right, the jury should not be permitted to infer from such an assertion any consciousness of guilt or tacit admission.” Id. at 902. Clearly, it was not evident that the defendants here asserted their rights, and therefore the jury could not have drawn any inference of “tacit admission.”
Even if the jury could reasonably infer that the Warrens relied upon their fifth amendment rights, their silence would not have been the silence that speaks. They had not been confronted with accusations or even questions. Since the Warrens did not testify at trial, that they might have chosen to remain silent after their arrest could not impugn an exculpatory explanation offered to the jury. This case, therefore, is not like Doyle v. Ohio, 426 U.S. 610, 96 S.Ct. 2240, 48 L.Ed.2d 91 (1976); United States v. Hale, 422 U.S. 171, 95 S.Ct. 2133, 45 L.Ed.2d 99 *1074(1975); Chapman v. United States, 547 F.2d 1240 (5th Cir.), cert. denied, 431 U.S. 908, 97 S.Ct. 1705, 52 L.Ed.2d 393 (1977); or United States v. Impson, 531 F.2d 274 (5th Cir. 1976). In those cases, error was found because “the point upon which a defense was being constructed, [the exculpatory testimony of the defendant], was arguably damaged or impeached by proof of the defendant’s silence when arrested.” United States v. Impson, 531 F.2d at 276. This case comes within the distinction we made in United States v. Griffin, 530 F.2d 101, 103 (1976), where we said, “Unlike the prosecutor in [United States v.] Hale, [422 U.S. 171, 95 S.Ct. 2133, 45 L.Ed.2d 99 (1975)] this prosecutor did not develop the prejudicial picture of an accused remaining silent in the face of police interrogation at the time of the arrest.”
D. The Bruton Issue
The issue for determination here is whether Bruton v. United States, 391 U.S. 123, 88 S.Ct. 1620, 20 L.Ed.2d 476 (1968), required the district court to grant John Warren’s motion for severance after Agent Battell related at trial Thomas Warren’s comment, “We are all in this together.” Record, vol. 2, at 214. Thomas Warren made this statement during his initial conversation with Agents Battell and Wallace, just after he, Thomas Warren, had produced the three pistols. We hold that the admission of this statement did not violate the rule of Bruton.
Bruton established that a codefendant’s confession that implicates the defendant is inadmissible in a joint trial if the codefendant refuses to take the stand. Implicit in the holding in Bruton is that the codefendant’s confession would have been inadmissible against the defendant in a separate trial. See id., 391 U.S. at 128 n. 3, 88 S.Ct. at 1623; United States v. Archibold-Newball, 554 F.2d 665, 677 (5th Cir.), cert. denied, 434 U.S. 1000, 98 S.Ct. 644, 54 L.Ed.2d 496 (1977); United States v. Scholle, 553 F.2d 1109, 1119 (8th Cir.), cert. denied, 434 U.S. 940, 98 S.Ct. 432, 54 L.Ed.2d 300 (1977). Although we recognize that it is not true that all evidence admissible in a separate trial under exceptions to the hearsay rule necessarily comports with sixth amendment confrontation requirements, see Dutton v. Evans, 400 U.S. 74, 86, 91 S.Ct. 210, 218, 27 L.Ed.2d 213 (1970), it is established that statements that are admissible under the coconspirator exception to the hearsay rule do not run afoul of Bruton. United States v. Archibold-Newball, 554 F.2d at 677; United States v. Scholle, 553 F.2d at 1109, 1119-20; Park v. Huff, 506 F.2d 849, 860 (5th Cir.) (en banc), cert. denied, 423 U.S. 824, 96 S.Ct. 38, 46 L.Ed.2d 40 (1975); McGregor v. United States, 422 F.2d 925, 926 (5th Cir. 1970); see Dutton v. Evans, 400 U.S. at 85-88, 91 S.Ct. at 218-19.
Fed.R.Evid. 801(d)(2)(E) makes admissible against a party “a statement by a coconspirator of [that] party during the course and in furtherance of the conspiracy.”14 See Krulewitch v. United States, 336 U.S. 440, 69 S.Ct. 716, 93 L.Ed. 790 (1949). Unquestionably, Thomas Warren’s statement was made while the conspiracy was viable. As we said in United States v. Arias-Diaz, 497 F.2d 165, 171 (5th Cir. 1974), cert. denied, 420 U.S. 1003, 95 S.Ct. 1446, 43 L.Ed.2d 761 (1975), “a person’s role in a conspiracy ends with his arrest.” Thomas Warren made the comment shortly after the boarding and long before any arrests had been made and even before there was probable cause to believe that a crime of any type had been committed. See note 12 supra and accompanying text. Thus, the comment was clearly made “during the course of the conspiracy.”
The closer question is whether the statement was made in furtherance of the conspiracy. To place the comment in the proper context, we reproduce the following excerpt from the transcript at trial. It follows Agent Battell’s testimony describing the boarding of the Stormy Seas, immedi*1075ately after which he and Agent Wallace approached Thomas Warren.
[MR. WHITTEN, the prosecutor:] What was the conversation you had with Mr. Tom Warren?
[AGENT BATTELL:] I asked him if he had any guns aboard.
[MR. WHITTEN:] What did he say?
[AGENT BATTELL:] He replied in the affirmative and took myself and Mr. Wallace to the deck house where he showed us three pistols.
[MR. WHITTEN:] Did you have any further conversation with Mr. Tom Warren about anything else?
[AGENT BATTELL:] Yes, I did.
[MR. WHITTEN:] What was the subject matter of that conversation?
[AGENT BATTELL:] Mr. Warren stated that — Mr. Warren expressed confusion. He said, “What’s this all about? We are all in this together,” and he exhibited —
Record, vol. 2, at 213-14. At this point defense counsel objected on the basis of Bruton.
To place this testimony in fuller context, we refer to Agent Battell’s earlier testimony at the suppression hearing. Describing these same events, he stated as follows:
[AGENT BATTELL:] I stated, “Why do you have these guns aboard?”
Conversation ensued, in which he stated that he was going down to South America, I believehe [sic] said to Aruba, to make a land transaction.
Record, vol. 2, at 80. This is all the transcript reveals regarding the context in which Thomas Warren made the statement in issue.
Although the transcript is somewhat' ambiguous as to what Thomas Warren was referring when he said, “We are all in this together,” the most reasonable interpretation is that he was referring to the supposed land investment enterprise, which was proffered as a cover story. On the testimony in the record, any other interpretation would render the statement wholly gratuitous. When the statement is taken to refer to the land investment scheme, it furthers the narcotics conspiracy because it implies that the Warrens and Cruse were jointly participating in an alternative, legitimate enterprise. Indeed, the statement might have been an attempt to explain why three pistols, which had just been produced, were on board. Thomas Warren might have wished to give the impression that the guns were to be used by him, John Warren, and Cruse for protection while they were in South America transacting the land investment plan. In any event, since the testimony is susceptible of a reasonable interpretation that is consistent with the trial judge’s refusal to grant the motion for severance that he made when the statement came into evidence, we will not construe a cold record to the contrary.
The statement was properly admissible against John Warren as a statement made by the coconspirator, during and in furtherance of the conspiracy. See United States v. Pate, 543 F.2d 1148, 1149 (5th Cir. 1976). As such, it does not violate the precepts established in Bruton.15
*1076E. The Fed.R.Evid. 615 Issue
The Government concedes and the panel found that the trial judge committed error, in violation of Fed.R.Evid. 615, when he refused to exclude the Government’s witnesses from the courtroom during the suppression hearing. The rule, by its terms, is mandatory: “At the request of a party the court shall order witnesses excluded so that they cannot hear the testimony of other witnesses . .” (Emphasis supplied.) Defense counsel requested that the rule be invoked at the beginning of the hearing, before any testimony had been received. Record, vol. 2, at 14. The rule was later applied at trial. Therefore, the only issue before us here is whether the violation of the rule at the suppression hearing requires reversal. We hold that it does not.
The defendants do not seek a new suppression hearing. Indeed, it would be meaningless for them to do so, given the purposes of the rule. The rule is designed to avoid the testimony of one witness improperly influencing that of another and to aid in the detection of disingenuous testimony. See Geders v. United States, 425 U.S. 80, 87, 96 S.Ct. 1330, 1335, 47 L.Ed.2d 592 (1976); 3 J. Weinstein & M. Berger, Weinstein’s Evidence K 615[01], at 615-4 (1976). The effects of any such influence, would not be erased by a new suppression hearing, and the opportunity to uncover any such testimony has passed. What the defendants must be seeking therefore (they request no particular relief) is a reversal of the convictions and a new trial without Government witnesses. We decline to read such a draconian sanction — tantamount to an exclusionary rule — into rule 615. See United States v. Whiteside, 404 F.Supp. 261, 266 (D.Del.1975).
Since we construe the violation of the rule not to require the automatic exclusion of testimony, the defendants must demonstrate that the trial judge’s error created sufficient prejudice to require reversal.16 The defendants did not object at trial to the calling of the Government’s witnesses. They did not move for mistrial on the basis that the witnesses’ trial testimony was materially influenced by their exposure to the testimony of other witnesses at the suppression hearing. The defendants’ failure to denote prejudice is particularly significant given the unique opportunity afforded them by their access to transcripts of depositions of the Government’s witnesses that had been taken in connection with a state prosecution arising out of the same transaction in issue here. See Record, vol. 2, at 333-35. The defendants have pointed to no prejudicial effects of the trial judge’s failure to apply the rule at the suppression hearing; absent a showing of prejudice we shall not reverse these convictions.
F. The Currency Convictions
Several recent opinions of this circuit have invalidated convictions under 31 U.S.C. § 1058 (1970) for transporting or causing to be transported monetary instruments in an amount exceeding $5,000 without filing the report required by 31 U.S.C. § 1101 (1970). United States v. Schnaiderman, 568 F.2d 1208 (5th Cir. 1978), and United States v. Granda, 565 F.2d 922 (5th Cir. 1978), construed the language in section 1101 requiring that the failure to report be “knowing,” and that in section 1058 calling for a “willful” violation of section 1101, to *1077necessitate a demonstration that a defendant indicted under these statutes had knowledge of the reporting requirement and a specific intent to commit the violation. The cases went further to invalidate, as a matter of law, any convictions under section 1058 for violation of section 1101 “unless affirmative steps are taken by the government to make the laws’ requirements known.” Schnaiderman, 568 F.2d at 1211 (quoting Granda, 565 F.2d at 926).
So as not, by our silence, to impugn these holdings, we expressly invoke the concurrent sentence doctrine. Since the court imposed upon the Warrens concurrent sentences of eighteen months for the marijuana conspiracy and six months for the currency violations, we affirm on the basis of conspiracy convictions and pretermit review of the currency convictions.17 See Hirabayashi v. United States, 320 U.S. 81, 85, 63 S.Ct. 1375, 1378, 87 L.Ed. 1774 (1943); United States v. Kelly, 569 F.2d 928 (5th Cir. 1978).
IV. Conclusion
For the reasons stated above, we AFFIRM the convictions of John Warren and Thomas Warren. The panel’s dispositions of the convictions of David DeFina and Des Schick, reversing that of the former and affirming that of the latter, are left undisturbed.
RONEY, Circuit Judge, with whom SIMPSON, Circuit Judge, joins, dissenting:
I agree with the result and most of the legal reasoning contained in Judge Fay’s dissenting opinion. Because the majority opinion does not seem to have the breadth Judge Fay ascribes to it, however, I write separately to clarify the critical difference between the majority and dissenting positions, as I understand them, and to emphasize the significance of our decisions in United States v. Schnaiderman, 568 F.2d 1208 (5th Cir. 1978), and United States v. Granda, 565 F.2d 922 (5th Cir. 1978).
All seem to agree that although section 89(a), as written, would empower the Coast Guard to board any American vessel and fully search it, without probable cause, for any reason whatsoever, the broad statutory language has been judicially construed in a more restrictive manner: the Coast Guard’s power to stop and board vessels is limited to conducting safety and documentation inspections. Majority opinion at 1064-1065; dissenting opinion of Judge Fay at 1079; see United States v. Hillstrom, 533 F.2d 209, 210 (5th Cir. 1976), cert. denied, 429 U.S. 1038, 97 S.Ct. 734, 50 L.Ed.2d 749 (1977); United States v. Odom, 526 F.2d 339, 341-342 (5th Cir. 1976); United States v. One 43 Foot Sailing Vessel, 405 F.Supp. 879, 882 (S.D.Fla.1975), aff’d per curiam, 538 F.2d 694 (5th Cir. 1976).
Likewise, all agree that if circumstances arise during the course of such safety inspection that generate probable cause to believe that a violation of United States law has occurred, then, and only then, the Coast Guard may extend its inquiry, conduct searches, seize evidence, and make arrests. Majority opinion at 1065; dissenting opinion of Judge Fay at 1079; United States v. Odom, supra, 526 F.2d at 342.
Although some unfortunate phrasing in the majority opinion would indicate a “plenary” power to search without cause, a careful interpretation of the opinion and of the cases therein relied upon show that it supports only a “plenary” power to stop, a principle with which we all agree. The majority’s statement that without reservation section 89(a) is constitutional, read in *1078light of the cases cited and the immediately subsequent statement that the Coast Guard may board vessels for safety checks and then, if probable cause arises, make further searches, clearly indicates the majority did not mean to change the law from that announced in United States v. Odom, supra. Had the majority intended to authorize the Coast Guard to make complete searches of vessels without probable cause, the present search could have been upheld without any further discussion. But the majority opinion carefully explicates the initial stop as a safety check, during which the agents acquired probable cause to conduct a further search.
It is here that the majority and dissent differ, and it is here that I agree with Judge Fay that the search and seizure were unconstitutional.
In our prior cases, evidence of illegality was found either in plain view or during the course of the safety inspection. United States v. Hillstrom, supra, 533 F.2d at 210-211 (plain view); United States v. Odom, supra, 526 F.2d at 341-342 (burlap sacks containing marijuana discovered while looking for the main beam identification number); United States v. One 43 Foot Sailing Vessel, supra, 405 F.Supp. at 883-884 (plain view and “overpowering” aroma of marijuana on ship).
In contrast to these cases, the agents here were from the outset engaged in an affirmative investigation beyond the scope of a safety inspection, in which they sought out evidence of illegality through questioning the vessel’s occupants and searching the boat. Although the majority describes the agents’ preliminary search as “cursory,” there is no constitutional exception for “cursory” searches, even if this search could be considered “cursory.” Regardless of how one designates the search that took place before the questioning and the search thereafter, it is clear beyond dispute that the agents engaged in an affirmative investigation beyond a safety and documentation inspection, without probable cause. The Coast Guard was without constitutional authority to conduct such an investigation.
The argument concerning the presence of Customs and DEA agents seems to me of little importance. I would think it makes little difference if other agents board a vessel along with Coast Guard officers, provided they do no more than what the Coast Guard is permitted to do. That proviso invalidates the current search: the Customs and DEA agents conducted an investigation beyond the safety inspection, and since Coast Guard officers cannot do that, neither can the agents accompanying the Coast Guard. So long as the other agents do no more than the Coast Guard could, I see no problem of constitutional dimensions. If special expertise is thus available for detecting customs and drug violations during a permitted inspection, so be it. Cf. United States v. Hillstrom, supra, 533 F.2d at 211 (safety inspection, and seizure of marijuana in plain view during that inspection, not invalid because suggested by DEA agent, who suspected drugs might be on board). Any other rule could deprive the Coast Guard of the aid of other experts in the fight against crime, much as if Inspector Baynes of the Surrey Constabulary were prevented from calling on Sherlock Holmes for assistance.
Although defendant’s currency convictions should also be reversed under our opinions in United States v. Schnaiderman, 568 F.2d 1208 (5th Cir. 1978), and United States v. Granda, 565 F.2d 922 (5th Cir. 1978), unless the en banc court should choose to reject them, these cases bear even a greater significance when juxtaposed against the facts upon which the majority partially relies for probable cause. Schnaiderman and Granda hold that a person is not guilty under 31 U.S.C.A. § 1058 for failing to file the report required by 31 U.S.C.A. § 1101 when transporting more than $5,000 out of the country, unless the person had knowledge of the reporting requirements and a specific intent to commit the violation. Unless the Government makes the reporting requirement known to a defendant, we indicated that it may be impossible to prove beyond a reasonable doubt that defendant acted with knowledge *1079of the reporting requirements. In the present case, the agents only asked Thomas Warren if he had reported taking the money out of the country and filled out the proper forms, to which he replied he had not. He was never asked if he knew he had to report it, nor did the agents give him an opportunity to fill out the appropriate forms once they discovered the money on board the Stormy Seas. See United States v. Gomez Londono, 553 F.2d 805 (2d Cir. 1977), and United States v. San Juan, 545 F.2d 314 (2d Cir. 1976). Thus the evidence of a committed crime is considerably weakened, and does not deserve the reliance placed upon it by the majority opinion.
The majority refuses to confront these currency convictions under the concurrent sentence doctrine. I respectfully dissent from such use of the concurrent sentence doctrine. Although I am ready, I think, to retire the concurrent sentence doctrine entirely, it should not be applied in any event where convictions for entirely different offenses will undoubtedly affect a defendant’s future adversely.
One further note. I underline Judge Fay’s suggestion that the holding of a Coast Guard stop on the high seas at gunpoint to be not custodial is unsupportable in real life. “Whoever makes the regulations doesn’t row a boat.” R. Bolt, A Man for All Seasons, 29 (Random House 1962).
Agreeing with Judge Fay’s analysis that the facts in this record reflect an illegal search, that the admissions were the result of custodial interrogation, and holding that Schnaiderman and Granda require a reversal of the currency convictions, I would reverse.
. Agent Battell testified, however, that no search was conducted until the currency violation had been discovered and the currency recovered. Record, vol. 2, at 87.
. Agent Wallace’s testimony was corroborated by Cruse. Record, vol. 2, at 109. Ensign Ryan testified that the marijuana was found in a drawer in the galley. Id at 44. At some point a small vial containing cocaine residue was also found.
We must point out that the mere possession of a controlled substance beyond the territorial limits of the United States (three miles from the coast) is not illegal. Therefore, although the small amount of marijuana “aroused [Agent Wallace’s] suspicion somewhat,” its possession did not constitute an offense.
. Cruse testified that this conversation took place before the currency was discovered, but he was not certain as to the timing. Record, vol. 2, at 106-108.
. This 12-mile limit includes the territorial sea, which extends to three miles from the coast, and the contiguous zone, which extends from three to 12 miles from the coast. The United States exercises plenary power over the territorial sea, subject to the requirement that the *1065passage of foreign vessels may not be interfered with unreasonably. See Carmichael, At Sea with the Fourth Amendment, 32 Miami L.Rev. 51, 56-57 (1977). The power of the United States over foreign vessels in the contiguous zone is limited to the preservation of specific interests, e.g., the enforcement of customs and safety laws. See id. at 58.
The high seas lie seaward of the territorial sea and thus encompass the contiguous zone. Although vessels on the high seas are subject to the powers exercised over the contiguous zones and certain safety, navigation, pollution, piracy, and slave-trade regulations, no country may assert sovereignty over the high seas. See id.; Convention on the High Seas, Sept. 30, 1962, art. 2, 13 U.S.T. 2312, 2314, T.l.A.S. No. 5200. To maintain order on the high seas, therefore, each nation is charged with the duty of policing its own vessels. Convention on the High Seas, art. 10, 13 U.S.T. at 2316. It was in the performance of this duty, pursuant to the authority of § 89, that the Coast Guard boarded the Stormy Seas some 700 miles at sea.
It is imperative, in light of the background we have just given, to establish the precise context in which we decide this case. We deal with the boarding of an American vessel by the Coast Guard beyond the 12-mile limit. Therefore, this case does not involve the application of United States law in the territorial zone or in the contiguous zone, where the Coast Guard may rely upon statutory authority in addition to § 89. In particular, we distinguish those cases defining the authority of customs officers to board vessels, pursuant to 19 U.S.C. § 1581(a) (1976), within the 12-mile limit. See, e.g., United States v. Caraballo, 571 F.2d 975 (5th Cir. 1978); United States v. Stanley, 545 F.2d 661 (9th Cir. 1976), cert. denied,-U.S. -, 98 S.Ct. 2261, 56 L.Ed.2d 757 (1978). United States v. Tilton, 534 F.2d 1363 (9th Cir. 1976); United States v. Caraway, 474 F.2d 25, vacated on other grounds, 483 F.2d 215 (5th Cir. 1973).
. The arrests for the currency violation were valid. See note 17 infra. The defendants do not question the validity of the inventory search that uncovered the trash compactor, the plastic bags, and the incriminating documents. They merely claim that absent Thomas Warren’s admission that he had not registered the money, which they claim was elicited in violation of Miranda, no probable cause existed to justify the search that produced the envelopes containing the money. Brief of Appellant John L. Warren, Jr. at 25-26; Brief of Appellant Thomas Warren at 14. Since we find the ob-tention of Thomas Warren’s statement not contrary to Miranda, see Part III. B. infra, the search turning up the money was supported by ample probable cause. Since the inventory search is not questioned, we do not reach the issue of its propriety.
. We feel compelled to dispel what appears to be a misapprehension in Judge Fay’s dissent. The dissent terms “wrong” our statement that the defendants failed to contest the issue whether consent for cooperation with the Coast Guard was given. 578 F.2d at 1086. The record clearly indicates that the defendants never as much as adumbrated that consent was lacking. Quite to the contrary, in their en banc brief the defendants admit the following: “[U]nder 14 U.S.C. § 141(b), the Coast Guard may avail itself of officers and employees of any Federal agency as may be helpful to it in the performance of its duties . . . .” Supplemental Brief for Appellants at 16.
Of course, as we have indicated, the defendants did initially contend that the agents’ presence was unauthorized. It is, however, incumbent upon the defense to show that the boarding was illegal for lack of authority, and that such illegality, if found to exist, would call for the exclusion of any evidence subsequently obtained. The defendants’ broad, unspecific denial is insufficient to shift this burden of proof to the Government. As we said in United States v. De La Fuente, 548 F.2d 528, 534 (5th Cir.), cert. denied, 431 U.S. 932, 97 S.Ct. 2640, 53 L.Ed.2d 249 (1977), the defense carries an “initial, unshiftable burden of alleging and proving some fact sufficient to make a prima facie showing of illegality. . . . [Djefendants must at least allege particular facts which would tend to indicate some governmental impropriety];,] and . . . general, conclusory allegations based upon mere suspicions do not entitle a defendant to have evidence suppressed.” (Emphasis in original.) See Nardone v. United States, 308 U.S. 338, 60 S.Ct. 266, 84 L.Ed. 307 (1939).
. Two additional provisions of the United States Code define customs officers to include officers of the Coast Guard. They are 19 U.S.C. § 1401(i) (1976) and 19 U.S.C. § 1709(b) (1976). Neither of these provisions subjects Coast Guard officers to customs regulations. See note 11 infra and accompanying text.
. Although § 89(b) would apparently subject the Coast Guard to regulations of the Drug Enforcement Agency when' the Coast Guard enforces laws charged to that agency’s administration, we have found no DEA regulation comparable to 19 C.F.R. § 162.3.
. The defendants contend, as they must under the language of § 143, that because one of the avowed purposes of the boarding was to look for obvious customs violations, Record, vol. 2, at 74, 85-86, the Coast Guard officers were performing duties “relating to customs laws” and were therefore subject to customs regulations. Given our holding that § 143 cannot diminish Coast Guard authority over American vessels beyond the 12-mile limit, the defendants’ contention is inconsequential in this case. We intimate nothing as to the validity of the defendants’ argument where § 143 might apply.
. The source of § 89 is the Act of June 22, 1936, Pub.L.No.755, 49 Stat. 1820. As far as this case is concerned, it differs in no significant respect from § 89.
. Section 401 is repetitive of § 201 because the former merely amended a provision of the Tariff Act of 1930. Section 401 was thought, necessary to make the definition applicable to provisions of the Anti-Smuggling Act that did not amend the Tariff Act. See H.R.Rep.No.868, 74th Cong., 1st Sess. 14 (1935). Section 201 is now codified as 19 U.S.C. § 1401(i) (1976), and § 401 is codified as 19 U.S.C. § 1709(b) (1976). See note 7 supra.
. We note that the foreign possession of more than $5,000 is not, in itself, a crime. The crime is the willful failure to report such money at the time of departure from the United States. See United States v. Gomez Londono, 553 F.2d 805, 810 n. 7 (2d Cir. 1977). Therefore, Agent Wallace had no. probable cause to believe that the reporting provisions had been violated until Thomas Warren admitted that he had not reported.
Additionally, we do not think that Thomas Warren’s admission that he possessed approximately $7,000 was sufficient, even in light of the circumstances that generated Agent Wallace’s suspicion that the Stormy Seas was on a narcotics run, to create probable cause to believe that a conspiracy to import narcotics existed. The possession of $7,000 would have been consistent with too many legitimate purposes to warrant an arrest at the time the questions were asked. Moreover, even if we assume that there was probable cause to believe that the Stormy Seas was going to purchase narcotics in Colombia, there was no indication that the narcotics were to be imported into the United States, and importation is a necessary element of the substantive charge upon which the conspiracy indictment was based. See 21 U.S.C. § 952(a) (1970); Record, vol. 1, at 1 (Count I of the indictment).
. The trial judge denied the motion to suppress because he felt Thomas Warren’s responses to be voluntary. The court’s reasoning was that they were made in furtherance of the cover story that the voyage was for land speculation. Record, vol. 2, at 133-34.
. Technically, under the Federal Rules statements by coconspirators are admissible not because they fall within an exception to the hearsay rule but because they are not hearsay at all. See United States v. Brown, 555 F.2d 407, 422 n. 35 (5th Cir. 1977).
. We note that even if the statement were not admissible under the coconspirator rule, it is doubtful that its admission would contravene Bruton. The statement was hardly crucial to the government’s case, in contrast to the confession that was admitted in Bruton. See id., 391 U.S. at 128, 88 S.Ct. at 1623; Dutton v. Evans, 400 U.S. 74, 87, 91 S.Ct. 210, 219, 27 L.Ed.2d 213 (1970). John Warren was clearly implicated by Cruse’s testimony. He was serving as navigator of the Stormy Seas and had supplied a boat to be used to unload the marijuana upon return to the United States.
Moreover, the statement is not clearly and directly inculpatory of John Warren. He was not mentioned by name, and the statement did not refer to any criminal activity. We think this statement hardly more incriminating than one calling for the division of the proceeds of a bank robbery “four ways” among conspirators, a comment we held not to be directly inculpatory of a codefendant in United States v. Hicks, 524 F.2d 1001, 1002-03 (5th Cir. 1975), cert. denied, 424 U.S. 946, 96 S.Ct. 1417, 47 L.Ed.2d 353 (1976). See United States v. Grillo, 527 F.2d 1344 (5th Cir. 1976).
In sum, Thomas Warren’s statement was “of peripheral significance at most.” Dutton v. Evans, 400 U.S. at 87, 91 S.Ct. at 219. It added *1076insignificant, if any, weight to the Government’s strong case against John Warren.
. Our holding that a violation of rule 615 does not call for the automatic exclusion of witnesses or testimony is consistent with the principle that the failure of a witness to comply with a sequestration order does not alone render his testimony inadmissible. See United States v. Suarez, 487 F.2d 236 (5th Cir. 1973), cert. denied, 415 U.S. 981, 94 S.Ct. 1572, 39 L.Ed.2d 878 (1974). Whether to exclude a witness who violated the order is left to the sound discretion of the trial judge, and he ordinarily will not exclude witnesses without a demonstration of probable prejudice. E. g., United States v. Phifer, 400 F.Supp. 719, 734 (E.D.Pa.1975), aff’d, 532 F.2d 748 (3d Cir. 1976). Moreover, the failure of the trial judge to order a mistrial when witnesses who have violated sequestration orders nevertheless testify will not justify reversal on appeal absent a showing of prejudice sufficient to constitute an abuse of discretion. United States v. Eastwood, 489 F.2d 818 (5th Cir. 1973).
. The arrests in the present case were effected prior to our holdings in United States v. Schnaiderman, 568 F.2d 1208 (5th Cir. 1978), and United States v. Granda, 565 F.2d 922 (5th Cir. 1978). Even assuming that the convictions on the currency violation could not be upheld, the arrests and search in this case are valid. The validity of an arrest depends upon the reasonableness of the officers’ actions at the time of the arrest and not upon what a court may glean from a statute three and a half years later. This rule is well established even where the statute under which the arrest was made is later declared unconstitutional. Moffett v. Wainwright, 512 F.2d 496, 502 n. 6 (5th Cir. 1975) (quoting United States v. Kilgen, 445 F.2d 287, 289 (5th Cir. 1971)).