Hey, "climber", you don't seem like a slacker to me. Actually you seem pretty hardcore, planning for all the possibilities like that. (Take that as a compliment from an old guy.)

Lots of good advice has been given. I like what AROTC said about tools that are "non-weapons" yet very useful in a tight spot. I (as a Canadian, thus a foreign national) have taken heavy-duty paramedic shears through quite a number of US airport checkpoints and they never even opened my bag. They were focussed on swabbing my electronics (fine by me, my goal is an equal number of takeoffs and landings). If it's cool on a jetliner, it's cool anywhere.

Survival gear isn't all about hardware, though; clothing, bedding, light, necessary medications, water storage containers, etc. are rather more important.

FWIW, maybe you could store more "emergency stuff" in a sealed bag, without question, if your parents told the school what was going on, and basically demanded permission for this to be on hand. If you're expected to shelter in place, and there's no hidden agenda on your part, then this equipment is to everyone's advantage (yours, your parents', your school's). Your parents could be a useful resource here; and smart people make use of the resources available to them. (End of speech. :-)