If you've wanted to ask your school about phones in the classroom and haven't known how to start, this is the wording.
There's a letter you can send to a teacher or a principal, talking points for a meeting or a board night, and the questions worth asking about what the policy actually is and whether anyone enforces it. Send any of it as it is, or change it so it sounds like you.
The tone is deliberate. A complaint or a demand tends to end the conversation, so this reads as a parent asking a fair question and offering to help, which is the version that usually gets answered.
It's free, and you can use any piece of it on its own.