The other side of the coin on this. Cell phones as day planners are invaluable. So kids who have spent their lives organizing their schedules on digital calendars are being told "Oops! Sorry. You can't use that anymore. We caught someone else using it incorrectly."
Incidentally, I'm old enough to remember how every graphing calculator in the school had video games installed on them and half my class carried a gameboy someone on their persons. This is going to be pure wack-a-mole as a policy. Selectively enforced, with lots of high profile punishments for minor infractions and inevitably highly intrusive misconduct by individual teachers and principles. Richer, whiter students will almost certainly be exempted from the policy through loopholes. Poorer, blacker students will be shoved even more forcefully through the School To Prison Pipeline. Cops will inevitably get involved in the worst possible way.
And all of this will be sold as a means of "reducing distractions".