When I was going through High School in the early 2000s teachers had a box you had to put your phone into at the beginning of each class. Worked fine then, can't see why it wouldn't now.
When I've worked in classified environments, they'd have an array of phone-sized lockboxes right outside the classified area. Put your phone in, take the key (which is on a springy lanyard to go around your wrist).
I assume high school students would immediately invent The Key Eating Game or something, where you swallow the lockbox key for TikTok clout
When I was in highschool about a decade later we figured out we could just hand the teacher some ancient flip phone and keep our actual iphones in our pocket.
