I set my blind(s) up the day that I am going to hunt any given area. Though I agree that it is probably better to allow the animals to grow accustom to them that particular approach is impractical for the public land that I hunt. As the others have stated I suggest placing them in natural " niches" to allow surrounding vegetation to break up the blind outline...either that or cut out your own.
No problem with either of my Doghouses or the Penthouse and wind flap. Maybe in a hurricane but then......