Spatial awareness is a real trait among deer,they grow up knowing every stick,stump,tree,jump,trail, track crossing just like your dog knows when he gets out of the car to head without hesitation to the "burow with the rabbits in it" although he may not have been there for six months.
Blokes plonk themselves in spots where deer have walked and fed for years and the deer generally pick up on the blob immediately and do double takes with the very wary ones turning and leaving.
The trick is to use camo of a material that has NO sheen,that suits the surroundings and the wearer is covering the trail,feed area etc...not on it! There are big name brands that I refuse to wear due to 'sunlight sheen' that reflects light.
Caps with logos on the front are a no no as its a moving blob that can be picked out especially by sambar.
Yes I know blah blah blah I could shoot deer in wearing a zebra skin kilt too but if you want consistent results suitable camo is a decided advantage.
I have had deer (six fallow does) run and stop looking back over their shoulders at my mate,they stopped a couple of yards from me and without a clue. Also have experienced sambar within a couple of yards looking right through me with the wtf expression on numerous occasions. I have said it before and will again....without camo 90+% of my wildlife photos would not have been taken.
Any old effn how I just chased a b+t wild dog up the paddock for 400 yards 10 mins ago until it hit the bushline,the `64 was fairly itching too.