Apparently Valve silently updated VAC, and did a big wave of bans for CS:GO as a Christmas Present.
http://www.reddit.com/r/GlobalOffensive/comments/2q7flx/biggest_vac_ban_wave_in_the_history_of_csgo/
And a Valve employee posted this in response:
http://i.imgur.com/jksixbV.jpg
Now, I think it's pretty safe to say the original poster was just some troll, but the response from the VALVE moderator was pretty funny.