I have spooked deer walking in and had them return within a half hour like nothing happened. I like to get in the woods while it is still dark as night, sometimes it doesn't work out that way. I find that walking in the pitch dark spooks less than walking in while it is light out. They will circle you but not run away alot of times. They know that they can see better than you. How? I don't know. One trick I use is I sometimes have my hunting buds walk to my stand with me. When deer see the group move on through the woods they will circle and come right back. Deer can't count for some reason. I think it could depend on the area too. Mountain deer that don't come in contact with humans all year, seem to be more affected and will leave the area. Suburban deer deal with people all the time and will not leave, at least in my experience.