I'm a heavy smoker, and I'm pretty sure that I'm just screwed by the fact that even after showering and brushing my teeth deer can still smell the tar and nicotine that's soaked into my body. Theirs nothing I can do about it for now except pay close attention to the wind. But my belief is that odor(and we're not neccessarily talking about death breath like the wife has in the morning) that originates from our mouth is definately an alert to deer of human presence.But who knows maybe Gryan has a point.