Re: Many cruisers with documented vessels can not enter FL legally.
Florida has a NG program, but in every other state there is a domestic state force which is seconded into the NG. The NG program usually provides federal training, finding, and equipment to the state militias in exchange for the ability to have them seconded to federal service on request, and usually there is a "home guard" and/or "state guard" component who are also exempted from NG service, so they can remain home to defend their state. When a state's NG forces are federalized, they become active federal militia who are seconded to the regular military, an odd little dance of legalities which is codified under a series of laws that even recently aren't all available on the web, you have to go searching in repository/law libraries to dig them up.
Not in Florida. In Florida the NG has a special program under federal authority and order. In every other state, there is a military or paramilitary force under state control, which can be called up as a state force, or federalized under the NG program. If you are a citizen of any other state (usually a male citizen between ~18~45) you are in fact obligated to serve when called. In Florida? Nope, Spain didn't have any legacy of militia service. That came from the English kings.
Technically, there's both a "National Guard of the US" and a "NG" or some such intentionally confusing nomenclature to go along with that all. Part of the two-step to ensure that NG troops think they are regular Army under Army command with no split loyalties. I keep getting the bits confused--which is exactly what Uncle Sam wants. The later Mr. Lincoln made sure that "militia" would be a dirty word forever after they won the Civil War.