Wayne.B writes:

That area is a heavily used public beach as you probably know.

Not really public. The area I am talking about is from Atlantic Blvd in
Pompano Beach, south to Commercial Blvd in Lauderdale-by-the-Sea. This is
not "public" beach in that it is all private buildings on the waterfront,
from hi-rise condominiums to small old cottages. It is definitely not a
public park like the Ft Lauderdale beach.

Florida seems to have case law about the "wet sand" being public, though.
"Wet sand" being the high-tide wash and below. This is apparently what
lets you walk up and down the beach frontage that is all private. The "dry
sand" above the high-water mark is privately owned (in this area).

Boating laws being a mishmash of admiralty/federal/state/local
jurisdictions, I'm having a lot of trouble sorting things out.

I have also gotten a written warning about not having flares on board when
I was pulled over for speed in a marina basin. Later I read the USCG
regulations that boats under 16' in the daytime don't (legally) require
flares (although of course it is a good idea to have em).