I don't know why they are allowed phones in school, but they are.
Our grandson lived with us for a few years, from 13 to 15. The cell phone provider had an option which allowed parents to disable the kid's phone for certain hours. His was programmed to only allow calls to and from us and his mother. He didn't like it, but he didn't have the password.
What I found interesting about the video is the lack of reaction from other students. It tells me she's done things like this before, and the other kids were waiting to record the show.
I think it would have been better for the officer and the vice-principal to pick her up, chair and all, and transport her to the office. She'd be forced to do what she was told, and three adults would not have their careers in jeopardy because the special snowflake wanted her phone.