This has happened to me a number of times. I'm currently subscribed to an elementary school parent system for someone else's kid. So I get emails every so often about the child being tardy or absent. There's no way for me to stop these emails or communicate with the school or the parent. I gave up and just archive the emails as they come. They'll graduate eventually right?

Same deal with dating websites and job search sites, I had a guy use my email to sign up for what must have been a job aggregator. I found out about 15 different websites had "10 new opportunities waiting" for me.

It boggles me that there is no double opt-in for something like your children's school attendence.