Overview of school searches:
New Jersey v. T.L.O. , 469 U.S. 325 (1985).
School officials may conduct searches of students based upon “reasonable grounds” as long as the search is not “excessively intrusive.”
See also Board of Education v. Earls , 536 U.S. 822 (2002) (holding that a policy adopted by the school district to require all students to consent to urinalysis testing in order to compete in extracurricular activities did not violate the Fourth Amendment, but was reasonable).