Recently there was a thing where VAC would erroneously flag AMD’s antilag+ feature as cheating, and issue a ban.
AMD then quickly disabled the feature by default but now Valve also patched detection for it and is now, at least according to these patch notes, reversing the bans.
Yeah, nowadays I think it only affects that game, but older valve titles handed out instant bans on othet titles that used the same engine.
Cheating in one of the following Source games or a Source mod will result in a VAC ban for all games in the list below: Counter-Strike: Source Half-Life 2: Deathmatch Day of Defeat: Source Team Fortress 2
Similarly, cheating in one of the following Gold Source games will result in a VAC ban for all games in the list below:
Counter-Strike Counter-Strike: Condition Zero Ricochet Day of Defeat Team Fortress Classic Half-Life: Deathmatch Deathmatch Classic
https://help.steampowered.com/en/faqs/view/647C-5CC1-7EA9-3C29#application
