We had an outbreak on our cruise in December. I'm a little surprised that the cut the cruise short, but maybe they decided they'd really do some deep cleaning. They did everything they could to alert the passengers. They took off all condiments, you couldn't serve yourself anything. I felt so bad for the crew.
Come to think of it, maybe they ran out of mattresses, pillows, curtains, etc. One of the couples I met on board stated they stripped a room on their floor where a passenger had the virus. They said they took out the furniture, drapes, everything and replaced it with new ones. If they kept on having to do that, maybe they just ran out of supplies.