May I ask the area you live? Not having ice monitor/rink guards in my experience around the US is not allowed on public sessions. For the rinks I’ve worked at, if even one person is on a public session, you have to have an ice monitor in the vicinity, or you are liable for any injuries.
My home rink is in a huge metropolitan area so our public sessions are super crowded. Lower level skaters/hockey players can have private lessons, but they have to be in the coned off area in the middle. They can do single jumps if room permits, spins, no spirals. We also can’t have hockey pucks, sticks, food/drink, and no “weaving”. People also can’t play their music through the PA system because the music playing on public sessions are played in the front office on a CD. A lot of coaches just use speakers.
We have pretty strict rules but I worked in the rink for 5+ years and never had issues. Our rules are because of how extremely crowded we get.
This is an interesting conversation!
I live in South Carolina, and my rink is in a Plex center. The staff is usually working in the lobby area and I guess they monitor the other activity areas outside the rink as well. But if there are issues on ice, it's very easy to get staff involved. We've had a couple of public skaters injure themselves recently (no one's fault, just bad falls) and staff responded very quickly.
We also have to sign a waiver, so I guess that covers the injury liability. I do think rink guards would be nice though, but I also think we do pretty well without them.