[vreihen16]

I think at this point the authorities have realized that it is best to break up group quarantines (like ships and hotels), separating the known infected from the potentially-exposed. On cruises originating at a US port, I'm pretty sure that the feds would let the ship dock and deal with the quarantine on shore. What they do for cruises originating in Barcelona (OP's itinerary?) is another issue.

Another concern would be overseas health insurance coverage, since US policies might not apply outside of the country. Keep in mind that a helicopter evacuation from a ship at sea for a health emergency will cost you at least a shiny new 3-series if needed, so buy travel insurance that covers this just in case.

With that said, I can see the cruise lines converting these cruises into long "cruises to nowhere" if the virus becomes too widespread or there are travel bans to certain ports/regions. For those along for the ride, these types of itinerary changes usually come with 50% discount vouchers for your next cruise and free booze for all on the impacted cruise.

For those contemplating a Caribbean cruise and cheaping out on the passport, keep in mind that the cheaper passport card only works for sea/land border crossings into the USA. If you wind up having to be flown back due to an illness or premature cruise ending at a foreign port, you will need to go through the additional hassle of getting a full booklet passport at the nearest US Embassy before you can board a plane to fly home. Hence, I strongly recommend the full passport booklet, even if your cruise doesn't require it.....