searches “may in certain circumstances take place not only at the border itself, but at its functional equivalents as well.” Id. As an example, the Supreme Court noted that “a search of the passengers and cargo of an airplane arriving at a St. Louis airport after a nonstop flight from Mexico City would clearly be the functional equivalent of a border search.” Id. Although the Supreme Court applied these principles to find that the search in AlmeidarSanchez was not a border search, the principles announced in that opinion nonetheless compel the opposite result here, just as those principles have compelled the opposite result in every case challenging the search of incoming international mail at the airport of arrival. See, e.g., United States v. Smith, 29 F.3d 270, 273 (7th Cir.1994) (<HOLDING>); United States v. Gaviria, 805 F.2d 1108, 1112
holding that a search less four miles from the border was a border search where the vehicle was searched seven hours after crossing the united states border from mexico but continuously surveilled during those seven hours holding a month delay in search of a computer constitutional because probable cause continued to exist at the time of the search and no prejudice occurred holding that search of backpack constituted a search of defendants person and was not authorized by search warrant for premises holding that mere insertion of key was not a search or at least not an unreasonable search protected by the fourth amendment recognizing the search of incoming international mail at or near the arrival airport to be a search at the functional equivalent of the border