it's some versions are rated T, Call of Duty had some troubling aspects for a father of a 13-year-old who wanted to play it. So they came to an agreement.
On Boing Boing, a writer named Hugh Spencer mentions his son Evan's enthusiasm for Call of Duty, but also that his kid knows there are some aspects to it that might set off the parent radar. While Hugh mentions this is rated T, later versions of CoD are rated M (thanks to readers for pointing that out. I even have the damn thing.)
Hugh, meeting him halfway, considered the benefits and the drawbacks of the game. "I could tell that the content was accurate - but there was lots of shooting and blowing things up," he says. "But there was a fair bit of that during World War II. So it was undeniable that Evan was experiencing history and there was this teamwork factor ..."
Evan would get to play the game, but before that, Hugh had him look up the Geneva Conventions online, read their provisions, and then the two discussed its history and what they mean. "So the deal is that Evan has to fight according to the rules of the Geneva Convention. If his team-mates violate the Convention [assuming Hugh means online human players]then play stops and Call of Duty goes away for a while."
As nearly unenforceable as that sounds, a point is made. And it makes a point in a way that seeing a film or reading a book about war can't. You can discuss why characters in those two media would make the choices they did, but it's a different thing to explain the choices you would make - and then act accordingly.
Now, seriously speaking, I'm not sure Evan's going to be reading out the provisions of the conventions to his squadmates in a COD lobby before starting up a match. I'm not even sure how many of them are applicable in multiplayer, to be honest. (Is dominating an opponent "torture"?)
And in singleplayer, yes, I'm aware that CoD:WaW opens with the torture and execution of an American prisoner. But the point of principles is that they govern your conduct; they're not based upon your enemy's behaviour. It's what it says about you, and not them.
Kudos to this father for making this a reasonably teachable moment, one that allows his son to enjoy the appropriate pursuits he chooses while still addressing the legitimate concerns of a parent.