In my opinion, this is all a load of hogwash. It's already illegal to sell M-rated games to people under 17, and it's been like this for years (at least here in Canada.) You can regulate the sales of games all you want, but they key to not screwing up your kids is giving at least half a rat's ass about your parenting.
Edit: Ooops, coulda sworn I saw this in the "recent articles" page, sorry for the epic necro-posting.