A tad unrelated to school spying but something to think of...those customer cards at your local grocery stores? They sell those to health and life insurance companies. Car manufactures sell your driving habits to your car insurance company and it's tied to your name.

I was reading somewhere on .win where a guy loaded his new Toyota to his son. His son connected his phone to the vehicle. The next day, his insurance company contacted him saying they noticed someone else driving the vehicle who isn't on the policy. He said he wasn't necessary to add his son as it was a one-time situation and the insurance company dropped him.