I don't know that deer have to get use to them. I hunted a field this year for the first time with a blind and had no problems. I carried the blind in, hunted, watched 5 deer, my wife missed her shot and carried the blind back out. I can also set it up in the field at my house where I normally have it and shoot a deer the same day.
My advice for hunting from them is to close them up as much as possible and make sure you aren't back lit by an opening. Also, since you are down on the ground, move slowly and deliberately when deer are around so they don't see the motion.
For the most part, i don't think deer give a blind a second glance. I shot a doe at 20 yards in a field and my blind was not brushed in or in brush. It was setting next to a bush so it looked like just another bush. But I guess they would think it is a bush even if it was by itself.