Scottsdale Gun Club said this, after one of my friends mistook the Shirk for an M249. Once I clarified it was just an M16 with a belt upper, he calmed down. Turned out to be a pretty cool guy, as I brought 4 Mgs and had 9 people there with me to shoot. They charged $100/he for the RO to be there with us, but it was a wash, because of the lane fees being covered.
The guys had a great time, I shot very little, being the MG steward, and I get that the range has liability insurance they need to protect to stay in business. That's their call, and as you said, their rules because of their attorney. I like to support local ranges, but the indoor ones are pretty inconvenient for me. I live almost walking distance to the largest state run shooting range in the US, by design.
In all, I'd do it again, because it's a very controlled atmosphere.