I feel the need to collect FACTS on the whole base VAC ban issue.

I'm curious to know what is fact and proven, what is speculation and what is purely made up.

So first, there is this topic

It links base's banned account

From there I followed the "information" link on VAC. It states
What is VAC?
If a user connects to a VAC-Secured server from a computer with identifiable cheats installed, the VAC system will ban the user from playing that game on VAC-Secured servers in the future.
So I skipped through the list of valve anti-cheat enabled games. Quake Live is not on that list. Which can only mean two things: 1. the ban was NOT related to Quake Live, or 2. there is still another cheat detection for quake live running, which will identify as VAC, but not use VAC directly (or related to that, the ban was manual, but flagged as VAC afterwards).

Does anyone have detail knowledge on VAC, Quake Live anti cheat and can enlighten us?

Afterwards I read through the comments, where it was stated base said his account could have been ("was") hacked. Other comments said that would not be possible of today, to which again others answered, there are literally thousands of account overtakes a year and so it IS very possible.

-VAC ban
-At least one of base's Steam account games was tempered with in some malicious way (by whomever)

-Ban for Quake Live cheat
-Steam accounts cannot be hacked

What can you add to the list of facts?

(I will update the initial post with any new information)