Seems obvious, but how for out do the boundaries of the city go? If they go out to Mean High Tide, these aircraft are operating outside the city limits, because, generally speaking, they fly over the water, don't they?
This should be a pretty easy thing for CBR to determine. I would suspect that the city does not have the authority to regulate what happens offshore.
A better question is how *high* do the boundaries go? It's been a while since I've cracked the FAR's, but I think that regulation of flight activities is a federal activity, not a municipal activity. While the FAA will work with locals for traffic planning (ie, publishing preferred traffic patterns, noise abatement), I don't know that it can ban this specific type of flying activity over a particular city.