IRL deer are predictable mostly. They require 2 senses to verify a threat. If the get that, they run away without a lot of consideration.
those are most often smell + one of {see, hear}. For seeing, they sense motion more than recognition. Camo be darned, I don't think the smartest deer in the woods can tell a man from a tree if the man isn't moving and does not stink.

Not a hunter really -- its too much like work -- but taking pics and hanging with hunters, I know this much.