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.