Local airport authority pulled that trick one year, anything for $ income.
They closed the airport for a weekend. We packed up and safari to another airport.
We told the airport authority the RC event did not have enough insurance to pay for a busted glider and lost income from down time if an RC hit it. The authority would be named in the insuance claim.
They collected less in RC fees, and a lot of headaches, then the lost income from fuel sales at the self serve pumps. Plus every month for the next year we would put more broken RC fiberglass and engine parts that we picked up off the field on the airport managers desk.
Also a letter explaining the rules because they had received FAA $$ and allowed the airport to be closed to support a non-aviation activity.
The next year the RC promoter was told to look elsewhere, there are 4 RC clubs with runways in the valley, well away from GA airports.