[throwawaysnxcv2]

Maybe there's a technical solution for this.

Companies could give students a special form of (e)sim card where the school could disable data and block calls that does not go to family, emergency services etc. during class, and then unblock it automatically when there are no classes.

I'm sure it's not as simple as suggested above, otherwise someone would have made it already. But perhaps there is a similar technical solution for this problem, as parents and schools are unable to fix it on their own.

[hypertele-Xii]

Build a giant Faraday cage around the classrooms. Blocks telecomms.

[seanmcdirmid]

Then you’ll get a visit from the FCC.

[rationalist]

Faraday cages are not illegal, actively jamming by emitting ypur own signals is what the FCC cares about.

[egberts1]

No, they will not get a visit from FCC for any form of passive blocking.

Maybe in a banana republic, but certainly not in U.S.A.