501 U.S. 429 (1991), argued 26 Feb. 1991, decided 20 June 1991 by vote of 6 to 3; O’Connor for the Court, Marshall in dissent. What constitutes a “seizure” within the meaning of the Fourth Amendment? Police practices need not be “reasonable”—indeed, are not regulated by the Fourth Amendment at all—unless they are considered “searches” or “seizures.” In this case, which involved a growing antidrug police tactic known as “working the buses” (randomly approaching a bus passenger and asking him for identification and to grant permission to search his luggage), the Court took a narrow view of what constitutes a “seizure.”
Kamisar, Yale. "Florida v. Bostick." In The Oxford Guide to United States Supreme Court Decisions. 2d ed., edited by K. L. Hall and J.W.Ely Jr., 108. Oxford: Oxford Univ. Press, 2009.