I'm always extremely reluctant to buy into deer that people call cross bred. 🤔
I had the same reluctance - until I killed one and wondered what might happen because I had a Mule Deer tag and the Coues influence was obvious. Happens in AZ sometimes.
And there are arbitrary lines in places, like the one in WA, where one side determines blacktail, the other mule deer. As if they never cross to the other side. And get up to shenanigans.