VAC Enabled Games
Please see the Steam Store Valve Anti Cheat Enabled search term.
The Valve Anti-Cheat system is enabled for servers displaying the Secured shield logo. Using custom skins, sounds or maps and playing multi-player mods which do not modify core .EXE and .DLL files will not result in a VAC ban
Cheating in one of the following Source games will result in a VAC ban for all games in the list and your items from Team Fortress 2 will be removed except any items that have been purchased:
Half-Life 2: Deathmatch
Day of Defeat: Source
Team Fortress 2
Cheating in one of the following Gold Source games will result in a VAC ban for all games in the list:
Day of Defeat
Team Fortress Classic
Excluding the games listed above, VAC bans will only apply to the game the cheat was detected in. For example, a VAC ban in Modern Warfare 2 will not affect Modern Warfare 3.
Call of Duty: Modern Warfare 2 & 3
VAC is enabled on all multiplayer servers, public and private. Any modifications to the game other than editing config files can result in a VAC ban. Examples of such modifications include but are not limited to console enablers, VAC disablers, and server hosting mods.
VAC is enabled in both Open and Ranked mode. Using cheats or trainers in either mode will result in a VAC ban.