I'm pretty fine with restrictions on usage during class time - but not by direct remote control of such personal devices. The goal is to improve education and prepare children for life in the modern world. That can't be done without a smartphone, the most important item of most people that they use to run their lives. Today, many normal people don't even have desktop computers, they do everything on phones. That has privacy implications on what is reasonable to do with a person's phone - even a child has right to their privacy (in reasonable limits of course).