There are many cruise ships in the Pacific at the moment. There are six in Australian waters refusing to leave. They propose to fly passengers needing hospital care to mainland. In New Zealand passengers on a cruise were not allowed to disembark. Precisely for the reason you fear in Florida that they will spread the virus. Of course if there are your own citizens aboard that is another matter, but here they would be screened and have to produce a self isolation plan or be quarantined. Tough all round.