The indians used scent control. One of them was to stand in the smoke of burning sweet grass. As far as deer seeing edges and the ground being disturbed I think they can smell the size of a footprint like we can see them and tell what made it. Deer being spook by edges of light are easily proven because deer will stop at an edge and check what is ahead before proceeding. Smart deer will not go into a clearing which is nothing more than a light edge without being very cautious. Just read a book were a guy used a mountain bike to get to his spots. He gave credit to his successes to not leaving a trail. You can’t say the tires left no scent. They didn’t leave a track the size of a boot at the gate of a man. Older bucks are very observant. I’m just trying to pay attention to what impact I leave. The less the better.