The problem with this approach might be that it's not really teaching them to control their own urges. My parents used to limit my gaming to 2 hours a week, and I abided by that rule faithfully until I got old enough. Then I started playing games when they're not home. Then I got to college and became severely addicted to video games to escape my academic anxieties.
I knew people who had nearly no limits and had the same problem later on.
I think that this one can be solved only by teaching kids to do positive/needed things. By that I mean not just limit gaming, but more of teaching importance doing chores, homework, sleep, socialization and other such things. So it is not "stop gaming so you stare at ceiling" but "I did not done homework damm have to can't game yet" sort of thing.
