That's an interesting concept! Here in Ontario, Canada... it's my understanding that teachers have limited ability to take phones away from students... but they don't really want to because it becomes a liability issue. Some of these phones are worth $1000 and if the teacher misplaces it or another student swipes it, the teacher can be on the hook.

If the policy is that the student doesn't get the phone back at all, that changes things significantly.

That policy is commonly called stealing -- though it probably has a more specific label under law.

Schools traditionally have been implement civil-asset forfeiture for small stuff because people rarely kick up a fuss, and the schools can quietly hand things back when they do.

But if they start taking away people's smartphones there will be push-back.