I just stayed in Santa Monica and wanted to fly the P3S at the beach and pier. I went into the police station on the pier and talked to an officer about flying on the beach and he said that the police on the beach can ask you to land but can NOT force you to land or leave. He did say that the Santa Monica airport is very close to the beach and I should call the radio control to get permission to fly at the beach. The next morning I called the tower and told them what i would be doing. They asked when i would be flying(time of day), how high i would be flying, where i would be flying, how long i would be flying, and to call them back when i was done. They did ask for some other information if they needed to contact me for any reason. Once i did this i was setting up at the beach and a cop approached me telling me that i was not allowed to fly there and i told him that i talked to and officer about it and that i have contacted radio control at the Santa Monica air port and he said that was okay and i was fine to fly. I am pretty sure he call the tower to check if i actually talk to them but he never came back. So if you are planning to fly around Santa Monica i would call the air port first, they were very nice and told me that they can not say no to me flying unless it was over the run ways and that i had done what i needed to by contacting them first. so if you are going to be flying around Santa Monica just call the radio control tower first and have fun!