No they don't sleep in dens.
I guess the question is, do you want WT's at the expense of losing MD??
I think, overall in NA, there is a concern of MD being out competed by WT, which could eventually lead to the demise of MD.
That, in my opinion, is how you have to look at it, especially in Lowland, Flat areas, say like Cache Creek, Kamloops etc.
Terrain varies here in BC, like comparing areas like Cache Creek to Golden for example.
MD can survive way up high, in sub alpine, but they do need to come down for a time during winter.
WT's generally stay low (although I have seen them moving high, especially with those way up high cut blocks).
What I am saying is, there are some areas where MD will roam, that WT wont, but come winter, that changes.
The fact that WT have expanded should be evidence enough, that for the most part, simply said, WT are okay, and they aren't at risk of being over hunted.
But, it is a matter of opinion I suppose....do you want to hunt more WT areas in the future, and lose MD?
Or, do you want MD to stay where they traditionally have been, and help them exist way into the future??
Do you want to hunt MD in Cache Creek or WT's one day in that same area??