I wouldn't say people expect the owner to be onsite, but a lot of people expect an innkeeper to be onsite. That can be an assistant innkeeper or whatever title you want to give it. I travel alone a lot and don't want to stay at a place with no staff onsite at night. That's my preference. Regulations are in place about overnight staffing depending on your location and number of guest rooms.
As an innkeeper ... during the busy season ... booked solid every night ... there would be at least one issue come up with a guest in the middle of the night each week. Sometimes more. Examples that all happened between midnight and 6 a.m.: sick guest needed complete change of bed linens; toilet backed up and overflowing and guest did not know how to shut off the water supply; bathtub overflowing and leaking down from ceiling into room below; sick guest required an ambulance; guest decided to sit outside in the middle of the night and locked himself out of the place; a fight between one couple left one guest locked out, the other inside refusing to acknowledge the yelling and pounding, third guest thought there was an attempted breakin going on (got no sleep that night); NAKED guest stepped out onto the third floor deck / emergency stair and was locked out. That guy was hiding in the parking lot, hunkered down between the cars throwing rocks at the inn windows until he got my attention. Prize winner, that one!.