If you get VAC banned on a valve game,you will get banned on almost every valve game.
If you get VAC banned on MW2,BO,etc,it only affects the certain game.
I got VAC banned from CS:S and I'm also banned from Dystopia,TF2,Age of Chivlary,Spacewar and other random games.
https://i.imgur.com/UwE5Y0A.png
VAC is weird.
Note: I got VAC banned like 4 years ago,so things might have been changed