I have seen them blow at me for sure! but at squirrels, limbs/twigs falling from trees, and last year had 3 bucks running one doe during the post rut and she constantly blew for literally 5 minutes solid until she was out of my hearing range. Also had a spike buck come in feeding on acorns one year. He would feed for a while, pick up his head and blow and stomp (facing opposite direction of me/wind in my favor) then would feed some more and repeat the blowing sequence, and then he bedded down about 100 yards from me and about 3-4 times an hour would just blow while he laid on the ground chewing his cud??? Of course when I got up to leave the stand and he saw me and he never blew once just bounced off and away stopping to look me several times???