I would not like it if I wasn't allowed to let my horse run loose in the arena! At my current stable the turnouts are quite small and my horse has CRAZY energy. I HAVE to turn her out in the arena before I do anything with her, lol.
Our barn hours are 7am-10pm which is nice, because my schedule is always changing. I like being able to see my horse when I want to.
We also have a good one, don't feed someone elses horse. It didn't happen at my barn, I just heard it from someone. But someone gave a horse a treat, and it ended up choking on it and dying. So, I completely understand and respect that rule.
Uggh, at my old barn this boarder used to bring her dog and all's he would do was run all over the place, chasing cats, jumping on the feed bins, running in stalls, it was SO ANNOYING. If it's the owners dog, that's fine, but someone elses household dog...I don't know how they will react around my horse...I wouldn't want it there.
Clean up after yourself and your horse.
Shut off lights, music, shut doors.
I don't know what else, I've never really asked, lol.