I think heat is a factor too in the daytime, right? Strong suggestion you may not have thought of. when you do go to turn them out, walk them by hand around the whole perimeter before turning them loose so they see the whole fenceline and don't run the wire.
Yes, we always walk the fence line with new horses or our horses going to a new place before turning them loose.
I hadn't thought of heat but that's a good point. Ok, I can do the fence walking. I had two reasons for not wanting to turn them out until daybreak. The first as you said, I want them to see their new environment and secondly, I know this sounds bad but I want pictures:')