If you get sick at sea, what are your rights as a passenger?

When the Royal Caribbean Explorer of the Seas docked in Bayonne, N.J., on Wednesday (shown above), it likely wasn't soon enough for 630 of the 3,071 on board, who had experienced gastrointestinal distress during the 10-day cruise that was cut short by two days because of the outbreak.

The company apologized for the "disruptions" that rendered Royal Caribbean unable "to deliver the vacation our guests were expecting," and extended to all passengers a 50 percent refund off their cruise fare plus another 50 percent credit toward a future voyage. In addition, sickened guests who had to be confined to staterooms by illness will receive an additional credit of one future cruise day for each day of confinement on this trip. Royal Caribbean additionally said it would reimburse airline change fees and accommodations for guests whose travel home was inconvenienced by the change of travel plans.

Was Royal Caribbean's offer in the aftermath of the health scare on the high seas a reasonable response? What are the rights of passengers when something goes awry? If you're considering a cruise, here’s what you need to know:

Federal oversight is minimal. That's because almost all cruise ships are registered outside of the U.S. They're regulated by foreign nations in whose name the ships sail. So-called "flagging" nations include Panama, Belize and Liberia, which have lax rules, according to attorney Charles Moure, with the international maritime law firm of Seattle-based Harris & Moure.

You're bound by the terms and conditions on the ticket. The ticket is your contract, which limits liability. The rules also can be found on a cruise line's website. They’re an essential read. As the industry has expanded, there's been a push for more government control, but it’s a slow go. The fact that the U.S. Centers for Disease Control took the unusual step to board the Explorer of the Seas to investigate the mystery virus is a positive step forward, Moure says.

Taking the deal could weaken your right to redress.When a cruise line offers a refund or future travel discount, it’s not necessarily out of the goodness of their hearts. It doesn't mean you cannot file suit, but accepting the settlement could make legal action more difficult, according to travel industry expert William McGee, a Consumer Reports consultant. And you’ll almost assuredly have to sign a release waiving future action. Cruise lines are often willing to negotiate terms, and most settlements for illness outbreaks such as the one on the Explorer of the Seas are "reasonable,” Charles Moure says.

There’s limited time to file suit, and the venue might be inconvenient. The cruise contract spells out details of the time frame to file litigation, and the appropriate court. Most cases are heard in Miami, Fla., the main U.S. cruise port. You may have as long as a year to file, but some cases might have to be brought within weeks or months of your trip. "Courts have been very favorable to the cruise industry," Moure says, "upholding the terms on the ticket."

Consider travel insurance. Given the perils that could sideline your trip—such as the highly contagious Norovirus, natural disasters, political upheavals, and other medical emergencies—travel insurance may make sense. That's especially true if you’re planning an expensive once-in-a-lifetime excursion. First, check to see what, if any, benefits are available through your home and health policies, and your credit card. If you decide to purchase insurance, avoid commission-driven ones sold by tour operators, cruise-line representatives, and travel agents, and check out an online broker such as insuremytrip.com, which sells coverage from multiple companies. You can tailor a plan to your needs, ask about exclusions, and get a quote. If you become ill and need to be airlifted to a hospital or require hospitalization in a foreign country, your personal insurance might not cover the expenses, which can be astronomical, according to Moure.

There is a new passengers bill of rights. In May 2013, the Cruise Lines International Association (CLMA), an Arlington, Va.-based trade group, and its members, which include Royal Caribbean, Carnival, Norwegian Cruise lines and other major lines that embark from U.S. ports, adopted a 10-point “Passenger Bill of Rights,” which addresses travelers’ entitlement to basics such as back-up emergency power if the main generator fails, the right to timely information about a problem, the right to get off a docked ship for medical attention if there’s inadequate care onboard, and the right to a refund for trips cancelled or curtailed because of mechanical failures.

Mike McGarry, senior vice president of CLMA, says member companies are legally bound to comply with the pledge. To date, he says, cruise lines that have faced adversity on the sea have “met or exceeded” the requirements and no consumer lawsuits have been filed for failure to live up to the terms. However, William McGee is a bit more skeptical, saying the pledge has “no teeth,” and makes “no promises or guarantees.”

That said, there’s now legislation before Congress that would put into law provisions similar to those contained in the CLMA’s Passenger Bill of Rights. The bill, which is in the House of Representative and is part of the Cruise Vessel Confidence Act of 2013, would extend rights to all consumers who purchase cruise-ship tickets in the U.S.

—Tod Marks