even if I'm not actually getting busted?

Let me explain - Back in the early to mid season, deer would actually see or smell me before I'd see them. This no doubt resulted in the ritual weezing and stomping followed by the white flag. This is my first full year bowhunting so as you could expect, I'm getting a little smarter with each trip to the woods, hopefully at least.

Now... I'm not getting busted anymore but am seeing deer out of range. I have a spot set up actually inside the wrappings of a big Christmas tree like pine. One day last week I watched from 70yds away as 3 deer crossed a tall grass field leading to a cornfield. The odd thing is, it was15 min before sunseton a weekday, I was the only person out there, the deer were making their way towards the cornfield which is in the direction I parked and walked from, yet5 min after they came by me they all stealthily made their way back from where they came. I think they must've seen my fresh footprints in the snow when they were going to the cornfield and decided they weren't sticking around. What do you think happened? Mind you I was downwind and motionless the whole time.

Well, since then I've been back to the same spot once for a morning and another for an afternoon with no luck. The other question I have is - Since there's snow on the ground and my prints cross their travel route, have they figured out when and where I am even if they don't actually bust me there? My thinking is that like hounds, deer can probably tell how old a scent trail is?