Today Blizzard have wielded their +1 master hammer of banning, and have deactivated over 5000 Battlenet accounts for players who have been caught cheating and hacking maps in Starcraft 2.
The most prevalent problem in Starcraft 2 is maphacking, the practice of hacking your installed Starcraft 2 client so that you can see the entirety of the map in multiplayer contests. The video below is a replay from the perspective of a player using such a hack. At 1:13 the player moves the camera to look at the southern area of the map, and in the final seconds he sends his probes to attack a Barracks being built there, even though he hadn't scouted the area. He knows it's there because he's hacked his copy of Starcraft 2, and can see everything that the Terran player is doing.
Blizzard have been threatening to ban players for a while (opens in new tab) now, but now those threats have been put into action. Those caught cheating by hacking their client will face a permanent ban from Battlenet, and will be forced to buy a new copy of the game if they want to play again. Those who are thinking about cheating in the future can consider themselves warned, as Blizzard say on the Starcraft 2 blog (opens in new tab) , "m aintaining a stable, safe, and secure online-gaming experience for legitimate players is a top priority for us, and we'll be continuing to keep watch on Battle.net and take action as needed."