Also dug this up also;
343 Industries have posted a notice on Twitter, for those who are playing Halo 4 early, that a “technical glitch” is causing players to be banned across Xbox Live.
People affected by the ban not only include people who have gained access to the game legally. 343 Industries along with Microsoft are working on fixing the problem as we speak.
“Some folks playing Halo 4 today were banned in-game on accident. Technical glitch. We’re working on the fix and so sorry for the error,” read a tweet on the official Halo Waypoint Twitter feed.