There are more than a handful per year of kids accidentally killing a friend or classmate with a wrestling move.
I was knocked unconscious by a kid in 5th grade who did a pile driver on me. Kids are doing sheet like that all the time. I found in a quick search a few instances of kids killing other kids with wrestling moves, so it does happen. It's rare enough though.
The injuries from wrestling moves by people who don't know what they're doing can be pretty horrendous tho. And those happen pretty frequently.