When my son was in 9th grade he got held after school for having an air chuck. School official said it was a toke pipe. I raked him over the coals for being stupid.
A few years later same guy took sons cell phone away, not allowed in school. It wasn't even on. I told him my son WILL carry a phone in school, if it isn't on, so he can call home if a Columbine was to happen. His carried the phone until graduation.
Common sense is not taught in school. You have to have it to teach it.
It was a different time but I carried a pocket knife all thru school. No one knew I had it except my shop teachers.