Oh, from a practical standpoint it wouldn't, simply because the vast majority of Floridians don't go on cruises.
Well, let me clarify: Floridians go on those three day, Bahama ghetto cruises, but those are on ships which only sail to and from Florida (be it Miami, Tampa or Cape Canaveral), so they're likely to adhere to whatever mandates and directives are put in place by the state of Florida, just so they can keep operating. If the state says a cruise line can't demand proof of vaccination, they'll play ball and not require it. The end result is that Floridians will still be able to go on those three day Bahama ghetto cruises unabated.
The larger cruise lines may have their vaccine requirements, but the state can simply refuse them service and, in the long run, it won't have any real measurable impact on Floridians.
It would also send the message that, if you want to do business in Florida, you'll do so only if you follow Florida's rules...