Marketing for the Grand Princess cruise ship advises prospective passengers to "Expect the extraordinary" when they take sail. Last week, that promise was exceeded when helicopters lowered COVID-19 test kits to a poolside deck as the ship floated off San Francisco. Twenty-one passengers and crew members tested positive for the coronavirus.

This week, the ship docked in Oakland, California, and started disembarking passengers, to be sent for medical care or into isolation. But those cruisers weren't the only ones to face an extraordinary end to their vacation: Elsewhere, onboard COVID-19 outbreaks have sickened hundreds and sent luxury liners on desperate searches for ports at which they can dock.

The human toll from the virus is steep; so, too, is its effect on the public image and finances of the $45 billion cruise industry. The weight of the U.S. government is against it, with the State Department now warning all Americans not to travel by cruise ship. "It ain't pretty," Richard Fain, CEO of Royal Caribbean Cruises Ltd. said last week. "In fact, to use a technical term I learned in business school, it sucks."