Was visiting LA and got accosted by some heavies that say they work for "Filmla"??

I recently purchased a Canon Cinema Camera and had a CN-E lens attached and decided to have some fun videotaping my dogs having fun etc.. Everything was fine until 2 unmarked vehicles stopped and a couple of guys exited the vehicle and briskly headed in my direction.

At first I thought they were heading to meet someone but they went and basically surrounded me and asked me what am I doing here and who am I working for.

I was confused and asked them what are they talking about, they told me the work for some company called Film LA? and that I needed to show them the permit. I told them permit for what. They kept insisting that I need to have a paid for permit, insurance etc for filming in LA any scene. I told them I am just a tourist filming my dog running around.

They called me a liar and said I have to pay the permit for using a professional motion picture camera in LA. I tried to explain that I am just playing around with my new Canon C300mk3 and nothing I am doing is work related. At that point I decided to get out of dodge since I am not sure if this was some kind of theft attempt.

As I got in they were following me for quite some time, I was in a rental vehicle and was able to leave.

Am I in trouble? Not sure what is going on but I would figure they probably got the plate and might try to find out what hotel I am staying in. They kept insisting I am not allowed to use professional equipment without a permit/insurance. What's the deal here?