I find that most times. if you are in a treestand at a decent height, deer can walk all around you without winding you.
If there is a major downdraft blowing your scent right on the deer's head, yea well, your gonna get busted.
I can't tell you how many times I have had deer, including bucks, smell where I walked and even smell the tree steps that I climbed. AND I'M IN THE TREE, LOOKING DOWN AT THEM!

Deer can tell by your scent: Where you've been, and where you are. They tend to react mostly to the "where you are" kind.
Hunting downwind takes care of that for the most part.