concurring.
I write separately to raise the following points with respect to Parts II.B.2.a and II.B.2.b of the majority opinion.
I. PART II.B.2.a: LAWFUL-PRESENCE ANALYSIS
Although I agree that all law enforcement personnel at the Garcia residence were lawfully present at the time of the search, I doubt the continuing viability of any rule based, on the reasoning in United States v. Sanchez, 509 F.2d 886 (6th Cir.1975). At the time that Sanchez was decided, the Supreme Court’s plurality opinion in Coolidge v. New Hampshire, 403 U.S. 443, 468, 91 S.Ct. 2022, 29 L.Ed.2d 564 (1971), stated that if law enforcement personnel found items that were not named in the warrant and that were not found “inadvertently,” then they could not seize those items under the plain-view exception to the warrant requirement. Id. at 469, 91 S.Ct. 2022. Sanchez relied on Coolidge for the proposition that “[wjhen a law enforcement officer has prior knowledge of the existence and location of property which he has probable cause to believe is illegally possessed, as well as ample opportunity to obtain a judicially sanctioned search warrant, the Fourth Amendment mandates that he must follow this procedure.” Sanchez 509 F.2d at 890.
In Horton v. California, 496 U.S. 128, 110 S.Ct. 2301, 110 L.Ed.2d 112 (1990), the Supreme Court changed tack and held that inadvertence is not a necessary condition for a plain-view seizure. Id. at 130, 110 S.Ct. 2301. As we subsequently recognized in United States v. Bonds, 12 F.3d 540 (6th Cir.1993), in Horton, “the Supreme Court ... eliminated the requirement that seizures in plain view by a ‘tag along’ officer must be of evidence inadvertently discovered.... [A]ny discovery of incriminating evidence in plain view, whether or not the officer expects to find it in the course of a search, is admissible.” Id. at 571 n. 29.
It follows that if the federal officer is tagging along to execute the state warrant, and the federal agent stays within the bounds of that warrant in terms of where he or she searches, then he or she is lawfully present at the search regardless of whether he or she has probable cause to search for something else and regardless of what he or she may hope to find while assisting in the search.
This position was set forth by the Ninth Circuit in United States v. Ewain, 88 F.3d 689, 695 (9th Cir.1996). In Ewain, the *516defendant objected to the fact that the narcotics agents who had obtained a warrant to search his home for drugs invited the postal inspector as a tag-along. Through the course of the search, the postal inspector found evidence that Ewain was involved in mail theft. In rejecting Ewain’s argument the Ninth Circuit explained:
Now that Horton has eliminated the “inadvertent” discovery limitation in the plurality opinion in Coolidge, it no longer matters that the invited-along officer was looking for what he found, which thing was not described in the warrant. What matters is whether the officers looked in places or in ways not permitted by the warrant.
Id. (emphasis supplied). This approach makes sense. If the tag-along officer begins looking in places unauthorized by the warrant, then he or she is not lawfully present at that particular place at the time he or she finds the contraband; conversely, if he or she is searching within the bounds of the warrant, then anything he or she finds that otherwise satisfies the plain-view exception is admissible. As stated by the Ewain court:
If the officers looked only where they were entitled to look under the terms of the warrant, and where they would have looked for the things described in the warrant, then the privacy of the person whose belongings are searched in those places has already been lost, and another pair of eyes does not add to that loss.
Id. (citation omitted). The tag-along officer’s “presence is at most evidence bearing on the probability that the officers looked in places they would not have looked had they been searching only for the things specified in the warrant.” Id.
Applying this analysis to the facts of this case, the federal agents were lawfully present at the place from which they viewed the items seized at the search. The warrant was for cocaine, which can be found in the smallest of places. Further, there was no allegation that the officers searched in places on the Garcia property which were not authorized by the warrant. In this case, the majority opinion inquires into whether or not the tag-along officer had separate probable cause and whether or not the tag-along officer was looking for items different from those authorized in the warrant. These questions are no longer relevant after Horton.
I realize that post-Horton cases in this circuit have continued to rely on Sanchez in determining whether or not law enforcement was lawfully present for purposes of the plain-view exception. United States v. McLevain, 310 F.3d 434, 440 (6th Cir.2002); United States v. Ford, 184 F.3d 566, 578-79 (6th Cir.1999); Bonds, 12 F.3d 540, 571-72; Bills v. Aseltine, 958 F.2d 697, 703 (6th Cir.1992). Although we do not overrule Sanchez today, the parties are free to seek en banc review.
II. PART II.B.2.b: “INCRIMINATING NATURE IMMEDIATELY APPARENT” ANALYSIS
I agree that all of the documentary items seized at the Garcia residence were subject to suppression, because they did not fall within the purview of the plain-view doctrine. However, I am concerned with language in the majority opinion suggesting that the documents found in the footlocker containing mathematical calculations would have been admissible had the officer not testified that he “examined” them. Maj. Op. at 511. Such a conclusion stands in conflict with our holding that a document is not within “the plain view exception if it must be read in order for its incriminating nature to be determined.” Maj. Op. at 511.
*517In my view, one could not “instantaneously diseern[]” the incriminating nature of mathematical calculations written on a piece of paper. Maj. Op. at 511. One would still need to read the document in order to know that there were numbers on the paper and that those numbers expressed mathematical thoughts. Next the reader would need to think about what those numbers might represent. Only then would the reader arrive at the conclusion that the document is of an incriminating nature. Thus, like the documents conveying information through letters, the incriminating nature of documents conveying information through numbers is not immediately apparent. In my opinion, the fact that Officer Fowler acknowledged that he “examined” these documents is not outcome determinative, but rather, expresses what anyone would have to do in order to ascertain the incriminating nature of such documents.
III. PART II.B.2.b: HARMLESS-ERROR ANALYSIS
Although I agree with the majority’s harmless-error analysis, I would emphasize that, had Garcia and Irwin not been in the Suburban together at the drug bust, the harmless-error question would have been a much closer call. The government pointed to the testimony of Dale Irwin, Oscar Nombrano, and Rickey Nombrano in support of its contention that admission of the Cheetah Transportation invoices was harmless error. But these witnesses were all involved in the drug conspiracy and received favorable treatment in exchange for their cooperation. Joint Appendix (“J.A.”) at 2377-78 (Irwin Test, at 14-15); J.A. at 1922 (Oscar Nombrano Test, at 151); J.A. at 1994, 1998 (Rickey Nombrano Test, at 65, 69). This arguably undermined the credibility of these witnesses in the minds of the jury. The fact that Garcia and Irwin were in the Suburban together is strong evidence corroborating their relationship with each other. Accordingly, I agree that the use of the Cheetah Transportation invoices to establish a linkage between Garcia and Irwin was harmless error.