What gives me anxiety is getting busted while I'm in the tree in the dark and the odds of that happening go way up when you can't see your surroundings.Talk about anxiety... this is exactly how I feel. I'm scared and I'm not affraid to say it. I'm waiting for @Bwhana and maybe a few others to chime back in.
Nothing worse than having a deer (that I couldn't see or hear coming) pick me off in the tree because I moved to scratch my nose or whatever. Having a deer stomping and snorting at me in the pitch dark sucks. Is is a fawn or the mature buck that I just screwed up on? Who knows? Cant see 'em.
You need to apply tactics to the situation. Sometimes, it may be better to go in an hour or more AFTER in gets light. I have a field that deer are in from late afternoon, all night, and into early light. There is no way I can walk thru that field during "normal" access hours. But if I wait until well after light I can pull off mid day hunts which can be dynamite during the seek/chase phase and post rut (freezing cold weather).
And sometimes a super early access is what you need to do. Know your herd as best you can, and be extremely careful to not educate them to the fact they are being hunted.