Many countries in East and South-East Asia are tying to deal with the issue of on-line gaming. South Korea, a democracy for all those raging against the "communists," has considered, but not yet implemented, a similar system. I have been in Internet cafes all across Asia and every time I am the only one in there checking my e-mail or web browsing, the rest are playing on-line games.
My biggest complaint is that they are playing crappy games which are nominally free, but you can use real world money to buy in-game items and advance faster. Ironically part of the problem is that parents refuse to buy consoles for their kids, but buy them all computers so they can do their homework. On-line games also account for a ridiculous percentage of the games made by local game developers in East and South-East Asia; they are cheap and easy to make and they pump out dozens of titles a year.
If Vietnam really wanted to solve this "problem" they should address some of the underlying social problems that they kids are facing. To get into high school, students have to take these gruelling entrance exams, then they have to take another set of entrance exams to get into one of Vietnam's limited number of universities. The last statistic I read said that something like only 20% of students get accepted into university. But then again, banning on-line games at night should magically clear up all of these problems.