They can sail, but the real questions are who's going to sign-up and what ports-of-call will let them disembark. It will be interesting to see if Carnival Corporation receives any bailout money for the pandemic at hand. This corporation includes sister cruise lines Cunard, Costa, AIDA, Princess and Holland America, I believe. But, overall it is considered a British/U.S. based corporation. From a personal standpoint, no one should be allowed to board a cruise ship unless they can show proof of being tested for COVID-19.