Im looking at you sokoudjou
http://mmajunkie.com/news/25461/after-failed-drug-test-ufcs-dave-herman-denies-use-rethinks-circle-of-friends.mma
If the weed is so strong at teamquest peewee got popped for a contact high I worried about hendo.
I would hope if someone was smoking near him he would either leave or the smoker would out of respect for his upcoming fight. 
I thought that was a urban legend though? Can you really fail a test by being around weed?
It would have to be so smoky that anyone would find it uncomfortable. Handling lots of weed, some would adsorb into the system as well. Herman works as a trimmer out there to get extra dough between training sessions and he should have wore gloves.