His mom was damn cool about the whole thing and it turned out quite well for everyone in the end, particularly as I was an additional voice poking him about homework. He got into the college he wanted and -- so on. I mean, I'm talking of course about a specific incident that went about as well as this sort of thing could ever possibly go, but this is in reality what actually happened the one time I ran into this as a game administrator. It was the only time it ever came up.
I was a TERRIBLE kid, and because I was a terrible kid, I know there isn't anything I could do as a game administrator to keep terrible kids out. It's just not possible, and beyond that, it falls into the realm of undue burden and such. It's just not reasonable.
So while I agree that there's probably things that could be done (and should be done in the cases of games that focus on themes that are popular with children) in the case of the prevention of harm to minors, I don't think it's really a privacy concern.
Legal, moral, and ethical obligations are all different sorts of obligations. It's important to be clear with ourselves on which we are discussing at any given time, since things can get muddied quickly.