My take on it is if they smell something they associate with danger they often flee, sometimes they hide. If they smell something new they may flee, may hide or may even come in to investigate.

Two of the leases I hunt have a lot of foot traffic, people doing nature walks, walking the dog; hunting Mushrooms, wild spices or Ramps. People smell doesn't spook the Deer much.

The other two leases, when/if the wind changes,you hear the Deer breaking brush and heading for the hills when they get your scent.

Mountain bike riders and joggers sure enough spooks them. Tractors, automobiles not so much.

One thing they might have to offer that is likely to be beneficial is a product that lessens the UV reflection on your clothes. Deer pick up movement fast, they see UV better than we do. Whiter and brighter laundry detergents not only have a scent, they make you reflect a lot of UV and glow in the dark to a Deer, likely to a Hog also.

I wonder if man smell pellets spread over a hunting area months before hunting season would lessen a Deers impulse to flee? I have no idea, they seem to have trouble associating some things with danger, like cars. They've been hunted by man for thousands of years and likely have a genetic tendency to avoid them?

Familiarity seems to lessen the instinct to flee.