I agree, the usefulness of this is questionable. Yeah, the deer may pass through...in the dark...but unless they bed down, or you're a poacher, what are you going to do about it?

I like to be in place and settled 10-20 minutes before legal shooting time. Even at that, I've had two occasions where bucks walked in, walked around me, or stood around, all well within range, then left before I could even see my sight pin. They never knew I was there, but so what? If you don't have a shot, it doesn't matter much, although the experience is a bit exciting, especially knowing that you must have done something right, since they didn't catch on to you.