My kid made a presentation for his class using Google Docs, then filled in his day of birth on his new phone when setting it up, then got locked out of his account. He was 12 at the time.

Also, his class had a WhatsApp group chat in which school info was shared. This was kind of weird because it meant that all 12 year olds in the group must have cheated their dates of birth, because otherwise they could not have had a WhatsApp account