This was a very annoying thing for me as well. Guests would routinely leave all lights on in the house, oftentimes sleeping with their room lights on and leaving lights and fans running in both the kitchen and bathroom at all hours. Had one time someone got up for a midnight snack and eight hours later, at 8 o'clock in the morning, found kitchen and bathroom lights on and both the stove and bathroom fans had been running all night.
I put this in my house rules and, in really bad cases, I do mention it to the guests, mostly stressing the fans in the bathroom are not designed to run constantly for hours at a time. Since it is now in the house rules, for really bad cases I could mention it in the review. Lights in the room I overlook, but leaving lights on in public spaces, and overheating the small exhaust fans by running them nonstop for hours is a serious thing.