Blizzard Entertainment has always taken cheating in any form in Blizzard games very seriously, and that's no different for StarCraft II. If a StarCraft II player is found to be cheating or using hacks or modifications in any form, then as outlined in our end user license agreement, that player can be permanently banned from the game. This means that the player will be permanently unable to log in to Battle.net to play StarCraft II with his or her account.
As is usually the case with mass banning, companies tend to wait before enforcing bans in an attempt to catch as many hackers as possible in one fell swoop. The company might lull them into a false sense of security, if you will, by seemingly not taking action. Since StarCraft II ownership is linked to specific Battle.net accounts, a ban will require the purchase of a new copy of the game along with creation of a new account.
There have been claims of map and drop hacking since the game launched. Hopefully, this should remove these rule-breaking players from the ladder environment and also render the hacks useless. I sincerely hope none of our readers have been engaging in any hacking. That would make me sad.