In my experience, deer seem to be very curious animals. In the dark they may spook, but chances are if you hear one snort, you were probably just as surprised as the deer because you were right on top of it. Unless your headed right for them and get very close, they'll just watch you walk by. In either situation, usually the deer return after daybreak to investigate what they saw. I usually try and be as silent as possible, but also get to where I'm going without messing around. I don't think the light affects them other than spark their curiousity. I've gone "spotting" before season since I was a kid. I can't recall a deer ever bolting off as soon as it saw the light, and thats one big flashlight. Seems to me they can be pretty bold in the dark ?