I don't really do it on purpose.
Night sometimes just sneaks up on me.
Even with a light I feel vulnerable. In the coop. In the dark.
Though the worst surprise encounter I've ever had in the coop was a sleeping skunk. (After eating 6 eggs and taking about a 5 hour nap he waddled off into the forest without misshap.)
Still, you never know what might be waiting for you.