There have been suggestions that it was fake, but I dont think so...he wasnt shoved, but he probably just lost his balance when the officer pushed his hand away. However, you can see in some photos that he had a tube running up his back under his shirt and coming out the side of his face mask into his ear.
I think it was some sort of communication device, either enabling him to record or broadcast his encounters (he kept tapping the police with his cell phone). So he wasnt working alone.