Who knows when it comes to the deer. I've had pictures of a buck that stood around and posed for several pictures. He didn't mind one bit but then I have another where I had the camera set up for double pics, in the first one he's walking, in the second one he's on his hind legs jumping out of his skin.
Of course the 35mm make noise too.
I think no flash is better but....like Greg showed, it still can be spooking. Look at the deer on the video ones, they look, get nervous etc....
Like I said, I have pictures of bucks that stood and posed for 5 or 6 pictures at very close range and I have one that a buck is turning inside out to flee at the camera flash/noise.
Who knows.