I’ve been at a lot of barns that claimed to do night check but didn’t. It frankly bothers me that horses can go, say 14 hours, without anyone checking on them, but that’s me. I’ve found enough injured/colicky horses after 6:00 to think it’s a good idea.
When I boarded, since I was often the last one in the barn, I just walked the aisle and checked all the horses before I left, made sure stalls were latched, etc., but I don’t think many people would think to do that. I’ve worked in a few barns and it’s just something I do automatically.
I have my (elderly) horses at home now and I always go down around 10:00 to check on them, throw hay and top off water. I usually give them a treat, too, as that will tell me real quick if someone isn’t feeling OK. Heck, since I live above them, I’m not opposed to running down in the middle of the night if I think someone isn’t quite right.
I once found my old mare caught with her head under her water buckets, waiting patiently for me to show up and get her up. I also had a gelding decide to rip his nostril nearly off. Had I not done a night check, both stories would have had very different endings.
I guess it boils down to how risk averse you are.