A friend and I got harassed by a local cop a while back. We were running our stadium trucks out on the street in front of his house. Out of nowhere a cop pulled up in the middle of the street and he was down right rude. He yelled, "GET THOSE THINGS OFF THE ROAD,(pause, nasty look)

YOU UNDERSTAND ME", or something along those lines. Then he just sped off after a few seconds. You would think that they would have more important things to do than harass people that are just minding their own business in front of their own house.
That's the only time I've come across a cop that was rude about rc stuff. Most cops think it's cool and say, "have fun", and drive off.
Sorry to hear about your run in with the cops, were you using those big RC duffle bags? That may have been what they were worried about, people tend to be scared of the unknown ie: not knowing what you had in the bag.