My first thought is that the DFW might have something to say about it. I know they have rules about scouting from an aircraft within 48 hours of hunting deer or big game or something like that. So I don't know if they would extend that to drones.
My second thought is that it would be pretty fun. But I don't know how practical/useful it would be.
What is the range of your drone (how far can it go away from you)?
How much time can it stay in the air?
Let's face it: if the drone has 1/2 mile range or less, it would be more practical to just walk it. By walking, you'll be able to see trails, tracks, scat, and rubs. I doubt you would be able to see all that from the air. If the dwell time of the unit is not long enough, you may not get enough time in the air to do any meaningful scouting. If your drone has a 2-mile range, and a dwell time of 2 hours, that's another story...
As for the ethical/moral side of the discussion, is it all that different than using a trail camera to scout? Maybe, maybe not.