I think initially the white flash may spook deer but if you think about walking out your front door and all the sudden "FLASH".... wouldnt that surprise you???
I agree that if you leave the cameras up long enough the deer will become accustom to the "flash" but then you have to worry about the 2 legged predators who wonder the woods in places they dont belong.
That is the sole reason I purchased an infrared flash so that someone wandering through the woods would have a little harder time finding my camera attached to a tree...