Apparently it has to be approved on both ends. MLG goes to Halo and says, "hey let's get this, this and this on the Pro Circuit" and MS says, "Ok, how about this and this but I'm not sure about this"
And apparently MS wants to push CoD over Halo. I know heard that somewhere but I'm not sure. It may have been a tweet from Sundance. However, I'm hearing MW3 just won't work on LAN because apparently you need a profile fully leveled up to 80 to unlock all of the guns. Even on LAN. Not 100% sure on all that but all we can do it wait.