§ 287 (a) (3) of the Immigration and Nationality Act, 66 Stat. 233, 8 U.S.C.§ 1357(a)(3), which provides for warrantless searches of automobiles and other conveyances "within a reasonable distance from any external boundary of the United States," as authorized by regulations to be promulgated by the Attorney General. The Attorney General's regulation, 8 CFR § 287.1, defines "reasonable distance" as "within 100 air miles from any external boundary of the United States."
