Interesting variance in perceptions and experiences from the many states represented.
Here we have to wear 250 sq inches. Hat and vest!
I'm a firm believer that deer, and a lot of prey animals learn from experience. IF an old doe busts you in a particular tree, she'll check that tree for you before coming thru or detour around that site.
I also believe that they see, according to research, the FLUORESCENT orange as a rather bright white... if it moves: BAM! Busted!
With the many deer/human encounters where I hunt, if they've associated that bright white-ish blob with danger, when they see it again, they seem to go on alert!
NOBODY knows what's in a deer's mind, but my experience is "some do notice, some don't" so I'm inclined to believe it's an "experience" thing...bad experience with that bright blob, they notice in the future...if none, it doesn't seem to bother them...
YMMV