Well, that is true in some cases. Deer in park settings can completely lose their fear of humans, particularly if it closed off to hunting. And I have even read where taking casual, loud walks (as opposed to stalking) like you do can condition deer to humans. I was hunting in a fishing area by a river once on public land that also was near where people fed deer. I had a spike buck walk within 8 ft of me, clearly seeing me the whole time. I finally made a move and off it went. An hour later when I was packing up, there it was, looking at me. And other deer in that area were not too spooky either. Of course, those kind of deer don't last long if the woods are public like these were. I go jogging and I have run within 10 ft of a deer standing in a ditch on several occasions. But in the next field a deer will bolt from hundreds of yards or even a near 1/4 mile away at the back of a field as I run by. Deer, like any animal, can unlearn its natural fears. Or it can gain an elevated fear. Like the mature doe that busts you -the next time she comes by your tree stand she will be listening for your heart beat! In my backyard, it is the latter situation where the deer are very spooky. Was not always that way but it is now. And I have a feeling that for the original poster, he too is in that situation where the deer are all spooked up. Perhaps his land lacks great cover, so with some pressure, they are pushed into heavier cover in surrounding land, only to return in the safety of darkness.