The second thing was my first thought. As an adult the idea of not having my phone causes extreme anxiety because it's needed for my medical devices. It'd be even worse for a teenager at school, especially if their insulin pump is only app controlled and they want to be able to eat lunch.
This is more on the parents not making use of built in controls. I have my niece's and nephew's phones set so they can only make calls, send texts, or use school related apps during school hours. Everything else is grayed out.
It's not rage, it's amusement from watching the slow motion train wreck.