Valve has just revealed in their official Steam forums that Counter-Strike: Global Offensive VAC will be different from the one employed in Team Fortress II and Counter-Strike: Source.
"After further review we have decided to remove the link between Source VAC bans and Counter-Strike: Global Offensive. The FAQ linked by heffebaycay has been updated to reflect this change.
Counter-Strike: Global Offensive is now a unique ban and bans in other games will not affect your ability to join VAC secure games in Counter-Strike: Global Offensive.”
The way Valve’s Anti Cheat (VAC) works is that if a player is caught cheating in Team Fortress 2 for example; his ban will carry over to other VAC-powered games like CS: Source and Modern Warfare 2. His Steam account will be tagged as VAC-banned, and the only way for the cheater to play again is to create another account and buy the said games a second time
Well banned users will rejoice after Steam’s Chadw revealed after a lengthy forum discussion that CS:GO will have a unique ban list and will not be covered from the previous VAC permaban. Meaning if you were banned in CS:Source, Team Fortress 2, MW2, Team Fortress Classic, Half-Life 2 Deathmatch etc, you can freely buy CS:GO and won’t have to worry about being kicked from VAC-secured servers.
Cheaters ftw! Now you will have a second chance to ruin further your account and reputation, as CS:GO’s beta for pre-purchasers will start tomorrow, August 14 PDT.