I have used Scent Killer ever since I had this interesting encounter: I had wounded a deer the evening before and was waiting just outside the woods for sun-up the next morning so I could track it. It was the first year I used Wildlife Research' s Scent Killer soap and spray.
As it began to get light I saw something moving toward me across an open field. I thought it was a small dog at first but it turned out to be a fox. It was upwind of me as it approached and, with their reputation for having super keen noses, I was sure that as soon as it passed and got downwind of me it would vanish. It walked within 15 feet of me to a pile of brambles which were precisely downwind and proceeded to hunt for mice in the pile. It stayed there for around 10 minutes hunting and never scented me, then just trotted off. I have been using that product ever since.
It' s always possible that the fox was hired by the company to sell me on the product. If so, it worked.