From the July-August issue of The Futurist:

Violence is on the rise in U.S. schools, and administrators are responding with tighter ... security measures such as metal detectors. ...

A pilot program was tested in five New York City schools during the 1989-90 school year in which a special security task force visited the campus on a rotating schedule and confiscated weapons found with hand-held detectors. No guns turned up in the schools, but approximately 200 weapons were recovered nearby, apparently dropped by students when they saw the metal detectors.

Many schools {are} locking all but the front entrance, installing better alarm systems, adding two-way intercoms in all classrooms, closing off little-used stairwells, giving walkie-talkies to playground and school bus monitors and getting rid of separate faculty bathrooms. Some schools issue every student an ID card that is checked by guards as well as requiring that visitors wear badges. Security measures at specific schools include:

Teachers at Fairfax Elementary School in Mentor, Ohio, prepare students to duck under their desks when they shout "earthquake drill!" The phrase is a euphemism for the possibility of an armed intruder. ...

In Winnetka, Ill., where a mentally ill woman entered unchallenged through an elementary school's rear entrance to kill one boy and wound five others, parents now take turns sitting in the reception area and screening all visitors. ...

In Greenwood, S.C., where a gunman killed two 8-year-olds and wounded nine other people in a crowded elementary-school cafeteria in September 1988, police officers now ... regularly visit the schools, eating lunch with students and walking the grounds.