Are gymnasiums meant to be supervised at all times?

I want to go to the gym this afternoon. I haven't been to this particular one for a couple of years, and have a feeling they'll tell me I need to be inducted (even though I go to a gym when I'm away at university) and that there's no one around to do it. So I want to prepare myself with a comeback; like 'aren't gyms meant be supervised at all times'. Any advice?