I do believe that deer become slightly accoustomed to some human odors like cigarette smoke, gas & oil. But I've spent alot of years in an elevated blind with a good view and have seen many, many deer cross my scent path downwind and react. Even when I dabbled in scent products I found them busting me at times.
I have also had deer cross my scent path while I was smoking and not pay any attention at all. For myself, I just face the wind and look behind me occasionally. The wind/air doesn't allways travel linearly so you never know.
I do wear camo 'cause they are my hunting clothes and it can't hurt, especially when still or bow hunting.