Every game has its rule breakers, and every game settles scores after the harvest, pursuing and banning those violators.
Often, just because you haven't been banned for cheating now doesn't mean you won't be banned in the future; it's simply that the officials haven't got around to it yet.
However, the vast majority of players who were banned would claim they were banned by mistake. A few even loudly complain on forums, ranting about the random bans, and then they flame wars with players who respond to their posts.
This situation was particularly noticeable on Day One of the new expansion.
Just on this day alone, the game officials announced nearly 50 permanently banned player accounts on the homepage.
The reason for the bans was uniform: modifying the game helmet on their own, violating the Player Conduct Rules that every player must agree to upon entering the game.
Those whose accounts had been banned re-registered new ones and started flame wars on the game forums.
