Brace from TrueAnon was sent to one, he talks about it on the series of episodes titled The Game. I first learned about them from the web comic that others posted, here. It's a struggle to believe, and the parents largely have no idea what goes on there either, but between just those two sources you'll see how fucked it is. Parents and the public at large are lied to about what it is, and since it costs some money, yes it is more affluent families doing it, and as has been said the kids are monitored and abused at all times and set against one another, while the guards are often former (well, current) victims of the system themselves, modeled after the very real cult that birthed it. It's harrowing to learn about but that it could produce someone so unstable and vengeful is sadly not at all surprising.