They need to be able to cite a specific municipal code or regulation that you are supposedly violating so you can look it up, and verify that it actually prohibits what you are doing. Can't just be a "policy." Once you are on solid ground (no...
I looked it up after I left the park because I saw nothing saying drones weren't allowed and I wanted to be courteous and stay within the rules.
Having said that, I didn't choose BAD Santa because I'm a goody two-shoes. I can be quite the Arse...
Assuming they have a written policy the city can tell you that you can't be standing on city park property launching/controlling your drone but they have no legal way to keep you from flying over the property. They have no jurisdiction over air...