Campsite Liability - insurance issues

[MobileBasset]

My RV insurer (National Interstate) tells me that when we rent an RV site we become liable for any mishaps on the site similar to at our homes, e.g. If a visitor trips on the fire pit and cracks his skull. They have coverage called "vacation liability" for those issues.
This got me thinking. When I rent a cabin in the mountains I expect the owner to carry the insurance. Why would RV sites be different?
My homeowners insurance agent (State Farm) is not familiar with that concept and says it may be a secondary coverage with the owner carrying the primary. she is researching it because I asked for a quote on the RV coverage.
Is this a real issue or is the insurance company intimidating me to double insure like they do for rental cars?

[jnharley]

We are full timers and carry separate liability insurance in case any one has an accident on our site. People who sue would probably sue all parties including you and the campground owner. This way, we are protected and our policy is inexpensive.