I would let them give you the citation and then fight in court, if it came down to that.
I have been hassled when shooting a building at night. The person wanted ID and who I was shooting for. I told them I was just shooting for myself and was a photography student.
I know that in the Hollywood area, if you try to setup and take some photos in front of famous landmarks, you can get hassled and asked for permits.
This has come about due to motion picture companies going way back in time. They used to film all over the place causing crowd problems. Not too far from my house McDonalds' has one of their restaurants just for shooting commercials. I have seen up to 4 Los Angeles Deputy Sheriffs controlling traffic in the area, just for a TV commercial. This is one of the reasons why Hollywood has lost so much filming business in the area. The cost of permits and hiring traffic control, off duty police for control has made the area too expensive.
Maybe next time they stop you while shooting, tell them the camera doesn't have any film and you can't figure out how to load the 35mm roll of film or where the flash card is supposed to go.