A policy that was put into use by United States schools and other establishments soon after the Columbine tragedy.
In practice, zero tolerance policies allow for no weapons or dangerous objects in school.
However, the noun "weapon" can mean "an object that can be used to cause harm"; the phrase "dangerous objects" is a plural of the same meaning; therefore, almost any object can be considered a weapon.
Because of this, overzealous officials often unleash horrificaly exaggerated sentences for the silliest of things.
A 7-year-old boy was suspended for pretending to shoot his classmates.