Not without breaking several laws, and potentially putting people in danger - how do you call 911 in an emergency if the school is in a signal blackout?
Landlines, voip, panic buttons. People made calls to 911 before the iPhone was invented.
When I was in school every single classroom was wired for landlines and Ethernet. You can also set up your wifi networks in ways that limit certain things and not others.
> When I was in school every single classroom was wired for landlines and Ethernet.
Alright, but they're not wired now. Neither are bathrooms, cafeterias, hallways, or other place where someone might have a stroke, a heart attack, a seizure. And unfortunately, gunmen in school are a thing, and if you're a teacher, scrambling for the wall-phone while you can hear gunshots in the next room over is significantly more difficult than reaching into your pocket for your phone.
When I was in school every single classroom was wired for landlines and Ethernet. You can also set up your wifi networks in ways that limit certain things and not others.