Lots of questions...

From what we know about the number, type and density of scent receptors in a deer's nose, a deer's sense of smell is as good if not better than a bloodhound's. Deer can certainly identify the differences in scent between different people. However, how they react to scent is very situational/spatial. By that, I mean deer learn where human scent (or an individual's scent) is a threat and where it is not a threat. When human scent is encountered over and over again in a particular location, and no threat is ever encountered in that location, deer will accept the human scent in that location without alerting. However, the same scent (even the same person's scent) in a new area will produce an alert response. It's all a learned response.

The biggest mistake hunters make is thinking about scent from a human perspective. We probably have the worst sense of smell of any mammal on the planet. We have lost much of our sense of smell over time, as our brain and verbal communication development has become a more critical aspect of our survival and social interactions. Our noses are so weak that our sense of smell is easily overwhelmed. This is not the case with deer. You CANNOT over-power a deer's ability to smell something by "covering it up" with a more powerful smell. A drug-sniffing dog can smell drugs suspended inside an encased tank filled with gasoline. A deer can smell human underneath even the most powerfull cover scent. For this reason, the idea of "cover scents" is totally bogus. THEY DO NOT WORK.