I think it was last year that either Field and Stream, or Outdoor Life had an article written by a deer Biologist, maybe someone else read it that can back me up. The article said something to the effect of if you startle a deer but don't scare it enough to make it run away, the deer will only remember to be on alert for about 5 minutes, after that it totally doesn't remember what scared them in the first place.

Like I said maybe someone else read that article and possibly remembers more about it than I do, but from what I can remember I think that was the gist of it.