Zero Tolerance=Zero Thought.

Literally--with a zero-tolerance policy in place, you don't have to think about it at all. You don't have to review the evidence, you don't have to make any judgement calls, you don't to basically do your job as a teacher or administrator. And if it's a bad call and parents get pissed, you have the rulebook to fall back on.

That's why in Georgia a student was expelled for having a "Tweety Bird" keychain on the grounds that it coule be used as a weapon. Another student was expelled for bringing a weapon to school--an eight-inch wooden bat from a baseball trophy.... and as a member of the baseball team he had several aluminum real baseball bats, designed and weighted specifically for striking things, in the trunk of his car, that they never had a problem with. Another student was expelled because she'd moved the previous weekend and accidently left a steak-knife in her car. I don't know if anyone's compiled all the incidents yet, but there are a lot