This debate will go on and on forever. There is basiclly no test that could put this to bed with definate evidence one way or another. A trail cam will only show what is infront of the camera, but not the deer off to the side that could become spooked. Everyone understands that most of the time, the old, large bucks, are the last to come by, letting the does and young to go first. How can you tell if these older larrger bucks are skirtting the cameras becasue of the flash, you can't really unless you see it happening with tracks in the snow or with your own eyes. I have read reports (more then one) where a hunter that had a trail camera close to his stand and watched bucks skirt the camera when it started to tack pictures as dusk.

Will it spook all deer ............ NO!!!!!!!!
Will it spook some deer ....... YES!!!!!!!

You need to deciede what you want in a camera, if it is for scoutting, then to be the least intrusive to your area and to get the most reliable results from the camera, I believe the IR cams are the best. But if ou only want pictures and do not really care if you spook the odd deer, then use a white flash camera, you will be ok.