Now recently we have been seeing this FAKE "Your account is VAC banned" message. It turns out from my own testing, you get this crap when you use CE. I have changed my squad points from 19 to 20 and changed it back to 19 again. 10 minutes later I get the great message...
So from this experience I would say everything in CE is "detected". Of course you can play with family share but you accounts are getting some sort of IW ban.
I would be happy to hear you thoughts and experiences on the topic!
CE was signed by user request 'cause antivirus will show up as malware/virus. But it seam that vac it self was changed, now is more intrusive in your system. Anyway CE can have acces even to Kernel (kernel debuger) so anyway will let trace on your system (USN jurnal) and seam vac will look for this entry now.
Was an old trick for steam, run it and close before log in for update, then run an older version from different folder and log in but i d'nt know if still work..