Well if you're going to a "glassing" spot, you can use what ever you want.
I've glassed guys hiking right on the fringe of feeding areas, using awesome looking green and red lights. They might as well used white lights as they kicked anything in there out.
I personally hike in with green. It's my preferred color. I have used red and it isn't as "helpful" as a green one to me.
There are times I activated the white light as I got turned around and couldn't find a ground blind I had just made. And neither red or green helped me locate my locaters lol
With all that said, I try to make sure thermals (down) don't blow them out, as well as intruding on feeding areas in general. I never hike in that close to them knowingly anyway and I can wait for them to get to me, and hope at same time the thermals have switched by the time they get to me. I have it timed pretty decent.