kids....
Bring your knives to school, its something...
as someone who actually has a tiny bit of sense of human morality and how guns work, literally any person shooting up a school would not loving flinch at a kid with a knife. he'd have shoot you before you could get out your knife, un-sheath it from it's sheath, and stab or throw it--not to mention most, if not all, people go into a state of shock when they are confronted with someone two feet taller than them with an assault rifle, hunting rifle, shotgun, or any gun for that matter. plus, they would be wearing at least some amount of armor so that your swiss army knife couldn't do stuff.
oh and do you have any idea how well-covered schools are to crack down on weapons?
for a school here, there are three armed police officers, and a metal detector at the door. unless you have a fiberglass knife that is disguised as a wallet, you stand no chance of bringing a knife to school.