[ImmNinjaxD]

I think it's not. Guards at my school do not check backpacks..

Same here, but after one of the shootings that happened ~3 years ago they cracked down pretty hard on security, so wouldn't be surprised if they have special cameras or something along those lines.

As for the most trouble I've gotten in:
In biology freshman year (a class of about 7 kids), our teacher stayed home sick and there was no sub to cover for the class, so it was a free study hall. Naturally we all took out our phones and someone was playing music at a moderate level. Things went fine for ~15 minutes until the VP came in and screamed at us all because she thought we were skipping class in an empty room, and we were all suspended for the rest of the day for "insubordination" because we tried to tell her the truth. Nothing too bad.

Besides that, in middle school I got a detention for accidentally hitting the drum major in the face with a paper wasp during band practice. Whoops.