Too many things we don't know about the situation - policies and how they've been enforced in the past, family vs school administration, community and state ed issues, previous incidents, etc.
As a private school, we declared such offenses '
could' result in suspension or dismissal - and tried to use common sense on a case-by-case basis when dealing with such matters.
As a part of the contract parents signed with the school, they gave us permission to search their children's backpack, person (not a strip search), and vehicle. We took their turst seriously and I never conducted a search (except for periodic random inspections of lockers or such) without valid probable cause. I never had a law suit brought against me, either.
We also brought a dog through the school 6-8 times per year for unannounced inspections of vehicles in the parking lot, lockers, common areas, class rooms, offices, etc. Only thing we ever found were a few periodic loose rounds under car seats or in a backpack in vehicles of students who had been out hunting at a ranch or such - I once found a hunting knife in a pickup which also had a couple of loose shotgun shells because the kid had been hunting the weekend before. I'd collect the rounds or knife, warn the students, and notify the parents to come by the office and pick them up - none ever gave me cause to dismiss them for this reason alone.
However, illegal drugs on campus = dismissal and - with probable cause - a refusal to have a drug screen = dismissal.
It's not a cut and dried world out there on campus - even though I would have liked it to have been that way on a number of occasions.
And so it goes...
Richard