(concurring in the result):
I am of the opinion that the use of a dog, trained to ferret out the presence of contraband drugs, for that purpose constitutes a “search” within the definition of the Fourth Amendment protection, and that the specific use in this case constituted an intrusion into an area in which the appellant had a reasonable expectation of privacy under circumstances which did not amount to probable cause. Hence, the search was unreasonable.
The law generally has recognized that the intrusion by Government agents into an area otherwise private by an artificial device which extends the personal senses is a “search.”1 For instance, the United States Supreme Court has so classified the use of mechanical listening or “bugging” devices which permit the listener to hear private conversations which he could not hear with his own limited senses. Katz v. United States, 389 U.S. 347, 88 S.Ct. 507, 19 L.Ed.2d 576 (1967); Berger v. New York, 388 U.S. 41, 87 S.Ct. 1873, 18 L.Ed.2d 1040 (1967). Similarly, an airport magnetometer which intrudes inside the clothing and handcarried luggage of air passengers and detects metal objects of a certain size, otherwise not discernible to the operator via his natural senses, is a search. United States v. Albarado, 495 F.2d 799 (2d Cir. 1974); United States v. Bell, 464 F.2d 667 (2d Cir. 1972), cert. denied, 409 U.S. 991, 93 S.Ct. 335, 34 L.Ed.2d 258 (1972). Whether our society will tolerate these various me*406chanical searches depends, of course, on whether in a given case the constitutional standard of reasonableness 2 is satisfied.3 I see no persuasive reason for calling a dog search anything but that: a search, permission of which, likewise, will be measured by its reasonableness. To pretend otherwise is to do in legal fiction what the ostrich does in fact.
The cases of this Court which factually have involved the question whether the use of a marihuana dog was itself a search within the stricture of the Fourth Amendment, upon careful analysis, support my belief in the affirmative. In United States v. Unrue, 22 U.S.C.M.A. 466, 47 C.M.R. 556 (1973), after studying a regulatory search procedure involving marihuana dogs in the initial stage of the search, which procedure was “ ‘carefully limited in time, place, and scope’ ”4 and which was designed to permit the subjects of the search an opportunity to avoid criminal liability, this Court concluded: 5
In our opinion, the Government’s use of the dog to detect odors from the vehicle that a human inspector could not detect through his own sense of smell was not unreasonable.
Immediately following this statement, Judge Quinn wrote the following, which rationalizes this position:6
In Katz v. United States, 389 U.S. 347 [, 88 S.Ct. 507, 19 L.Ed.2d 576] (1967), the United States Supreme Court held that an electronic device cannot be used by a Government law enforcement official to expand his sense of hearing to enable him to listen to words uttered by a suspect into the mouthpiece of a telephone in a public telephone booth. Since then, it has been suggested that no sort of a device can be used by an agent to enlarge the range of his senses beyond normal human limits. See Rintamaki, Plain View Searching, 60 Mil.L.Rev. 25, 37-38 (1973); cf. United States v. Loundmannz [153 U.S.App.D.C. 301], 472 F.2d 1376 (D.C. Cir. 1972). For purposes of this appeal, we assume that Katz erects a barrier against Orwellian surveillance that can result from indiscriminate and uncontrolled use by the Government of the myriad of devices which modern technology can provide to probe into the privacy of person and place. Perhaps Katz would prohibit the search of a pedestrian by a police officer on a public street in daylight hours solely because an x-ray device in a police van parked at the curb indicated that the passerby had a gun in a jacket pocket. At the same time, however, we have no doubt that Katz does not prohibit a police officer on a night patrol from using a flashlight to illuminate dark places on a public street in which a burglar might be lurking. See United States v. Wright [146 U.S.App.D.C. 126], 449 F.2d 1355 (D.C. Cir. 1971), cert. denied, 405 U.S. 947 [92 S.Ct. 986, 30 L.Ed.2d 817] (1972). Whatever Katz may or may not enjoin in regard to augmentation of human senses, the rationalizing principle for any case of Government ac*407tion that is opposed to the individual’s claim of privacy is the constitutional standard of reasonableness; if what the Government agent does is reasonable, there is no violation of the Fourth Amendment. United States v. Kazmierczak, supra.
Thus, although the Court did not expressly address the issue herein of concern, implied both in its opinion above first-quoted and in its rationale therefor which follows is that the use of the dog in that case was, indeed, a search. Otherwise, there would have been no reason for the Court to feel constrained to determine that the use of the dog under the circumstances was “not unreasonable.”
In United States v. Carson, 22 U.S.C.M.A. 203, 46 C.M.R. 203 (1972), a marihuana dog was permitted to check the baggage of the appellant and his two companions in a military airport terminal, after they had applied for flight space but before they had yet committed themselves to travel or checked their baggage. In fact, one of the three was with the luggage at all times while waiting in the terminal. This Court decided that the search which followed the dog’s alert was not a “customs-like” search, which was the theory of the Government on appeal. In so ruling, the Court found pivotal the facts that normally the dog did not check any baggage until after it was cheeked for a flight and that in that case the accused had not in fact checked his luggage, but rather had retained control over and possession of it. Although, as indicated, the use of the dog as a search was not determined expressly, the same consideration would have dictated the same result had the dog been viewed as the search instrument, that is, the accused had not given up his reasonable expectation of privacy in his locked luggage which remained in his possession and control.
Moreover, the rationale underlying the decisions of the Federal district and circuit courts in this area do not support a conclusion to the contrary, despite the purported holdings. For instance, the U. S. Court of Appeals for the Second Circuit in United States v. Bronstein, 521 F.2d 459 (2d Cir. 1975), responding to a claim by the defendant that the use of a marihuana dog was a warrantless search without probable cause, opined that if a police officer had smelled the contraband with his own senses there could have been no complaint and that the court perceived no difference whether the sniffing was done by a policeman or by a dog.
However, the court’s analysis of the facts and the law was not this simplistic. Based upon a reliable tip regarding two suspicious passengers en route to the destination airport, law officers thereat walked a dog past the luggage from the flight after it had landed and was waiting to be claimed. When the dog alerted, the two men subsequently were arrested. While an officer had left to obtain a search warrant, the two men consented to a search of their luggage. While purporting to hold that the use of the dog in that case was not a search at all, the court’s rationale for the ruling belies this position and indicates in reality that the search by the dog was sustained as reasonable on the ground that the defendants had abandoned their expectations to privacy in the luggage when they had checked it onto the flight.7
“What a person knowingly exposes to the public even in his own home or office, is not a subject of Fourth Amendment protection.” Katz v. United States, 389 U.S. 347, 351, 88 S.Ct. 507, 511, 19 L.Ed.2d 576 . and see United States v. Johnston, supra, 497 F.2d [397] at 398 [9th Cir. 1974].
Further support of what I see as the court’s true basis for its decision in Bronstein is found in footnote 2 of the opinion in which the court references a Federal district court opinion which squarely held that the use of marihuana dogs constituted a search:8
In United States v. Solis, 393 F.Supp. 325 (D.C.Cal., 1975), it was held that the *408use of marijuana-detecting dogs constituted a search per se under the Fourth Amendment. Aside from the fact that this case is not binding upon us, we note that the dogs in Solis sniffed at a closed trailer, which the court held to be a “private place” where there was a reasonable expectation of privacy. Moreover, the dogs were employed in response to a tip from an informer of unproven reliability.9
I believe, then, that logic compels and law supports the conclusion that the use of a dog trained to detect contraband drugs constitutes a search within the meaning of the Fourth Amendment. The only question to be asked in such eases, as in all search cases, is whether the intrusion into another’s privacy by the Government was reasonable. As there existed no probable cause to believe that the appellant was in possession of marihuana in his enclosed area in the squad bay, as none of the exceptions to the probable cause requirement is supported by the record, and as I have no doubt but that the appellant did have a reasonable expectation of privacy in his wall locker in that area, I concur in the disposition ordered by Judge Cook, but for the reason that under the circumstances of this case the contraband evidence was discovered and seized as a fruit of an unlawful search by the dog.
. This is to be distinguished from cases in which non-“Big Brother” types of instruments were used to heighten personal senses in order to survey an area which was not, under the circumstances, private. E. g., United States v. Lee, 274 U.S. 559, 47 S.Ct. 746, 71 L.Ed. 1202 (1972) (use of a boat searchlight); United States v. Hood, 493 F.2d 677 (9th Cir. 1974), cert. denied, 419 U.S. 852, 95 S.Ct. 94, 42 L.Ed.2d 84 (1974) (use of a flashlight to look into a car at night); United States v. Minton, 488 F.2d 37 (4th Cir. 1973), cert. denied, 416 U.S. 936, 94 S.Ct. 1936, 40 L.Ed.2d 287 (1974) (use of binoculars); Cobb v. Wyrick, 379 F.Supp. 1287 (W.D.Mo.1974) (use of a flashlight).
. U.S.Const. Amend. V; United States v. Kazmierczak, 16 U.S.C.M.A. 594, 37 C.M.R. 214 (1967); United States v. Hartsook, 15 U.S.C.M.A. 291, 35 C.M.R. 263 (1965); United States v. Battista, 14 U.S.C.M.A. 70, 33 C.M.R. 282 (1963).
. As to listening devices, for instance, sans probable cause which itself supports a conclusion of reasonableness, this search technique is not lawful, as it meets none of the non-probable cause exceptions and is indiscriminate in matter “seized.” The use of the airport magnetometer, on the other hand, has been rationalized as reasonable. Its use was born out of a substantial pressing public safety mandate; the conditions of its use — that is, under proper warnings which permit a passenger to rid himself of any items possessed prior to submitting to the device’s scan or to turn back completely — are restricted; and the matter “seen”— metal objects of a certain mass — is limited in scope. Most importantly, no passenger who is searched by this electronic instrument has a reasonable expectation of privacy vis-a-vis the limited intrusion involved.
. 22 U.S.C.M.A. at 470, 47 C.M.R. at 560, citing United States v. Biswell, 406 U.S. 311, 315, 92 S.Ct. 1593, 32 L.Ed.2d 87 (1972).
. Id. at 470, 47 C.M.R. at 560.
. Id.
. United States v. Bronstein, supra at 462.
. United States v. Bronstein, supra at 461 n. 2.
. If the use of the dogs was not viewed as a search, there would have been no need to discuss the private nature of the place sniffed or the unreliability of the informant upon which basis the dogs were sent to sniff.