Horton v. Goose Creek Independent School District

Fourth Amendment requirements differ, depending on whether the place in which a search and seizure occurs is a private or a public locale. And within public venues, schools present a special situation, in part because both law and judicial practice tend to grant lesser rights (but also a lesser degree of culpability) to minors.

A pivotal case in the development of law regarding school search and seizure is New Jersey v. T.L.O. (1985), in which a unanimous Supreme Court applied the Fourth Amendment prohibition against unreasonable search and seizure to public schools. But in the same case, a 6-3 majority held that probable cause is not needed to justify, or a search warrant to legalize, a search of a student by a school authority. Rather than probable cause, Justice White established a two-pronged test of "reasonableness" as a basis for searches.

Thus under T.L.O., the legality of school locker searches is predicated on the student's expectation of privacy. Searches of vehicles in the school parking lot are not considered unreasonable, and the California Attorney General in 1992 likewise applied the reasonableness standard to justify the placement of metal detectors as part of a generalized search for weapons.