Faced with this problem, different people may have different opinions.
I would allow them, but with some technology implemented to limit their accessibility. The easiest solution would be to install commercial-use cell-signal jammers into the classrooms. These could be small in area of effect, so after exiting the classroom, normal functionality would return.
Even if students carry mobile phones, they will not affect classroom order. But I don't know much about the device, and I don't know how much it will work.
First of all, I agree with you. Indeed, simply preventing students from carrying mobile phones is not ideal. It is easy to arouse the students' resistance.
At the same time, using a mobile phone jammer can quickly achieve the desired effect.
At the same time, this kind of jamming device has the ability to adjust the range, you can properly cover the range you need.