I am pretty sure they just changed something server side that prevents you from connecting if banned (similar to MW3). Xeno tested on his unbanned alt and connected just fine, so it's more than likely VAC related.
So far I have managed to patch the game to allow me to get into the game menus and etc. Some server stuff isn't activated properly however so I can't search for a match nor start a private one. Xeno said he managed to get private matches working but has yet to test with public matches. Progress w00t!