Dumb and dumber: Do these things on a cruise and you could be in a world of trouble.

You see this headline occasionally: “Missing cruise ship passenger falls backward off a railing.” The accidents usually are fatal.

But occasionally a miracle occurs. In August, a 45-year-old British woman survived a fall from a cruise ship, spent 10 hours treading water in the Adriatic Sea and was rescued, none the worse for wear. She credited yoga with keeping her alive, according to media reports.

Yoga or not, she was lucky. The water was warm, and a Croatian coast guard boat found her before it was too late.

She could have ended up a statistic, like others who have scrambled onto a cruise ship rail on a dare, sat on it to shoot a selfie, or climbed on it to make a little whoopee.

On our list of things you should avoid doing in your cabin or balcony, climbing onto the rail or the balcony furniture is at the top. But there are several other ways you can embarrass, injure or kill yourself and perhaps others if you’re not careful.

Lighting up in your cabin to smoke, burn candles or light incense is another dangerous act and is prohibited by cruise lines. Most bar passengers from smoking on their balconies too.

Many cruise lines have strict policies prohibiting passengers from throwing cigarette butts overboard because the wind may blow them back onto the ship, creating a fire hazard.

If you get caught smoking in your room or on your balcony, you could be left ashore as your ship sails into the sunset.

“Any number of things can get you kicked off a cruise ship,” said Colleen McDaniel, senior executive editor of Cruise Critic. ‘’But in truth, most of them fall into the category of common sense.

“Using drugs and becoming violent are surefire ways to find yourself booted. Other behaviors, such as being abusive to crew members, buying minors drinks, bringing weapons on board or smoking where you shouldn’t could also get you disembarked.”

Some things won’t get you booted but might prove embarrassing, including sunbathing in the nude on your balcony. You may think no one can see you, but that supposedly private space really isn’t private. Take a look the next time you’re on a balcony. It’s not difficult to see into fellow travelers’ verandas.

Other passengers can also hear you, which is a good reason to keep the music, lovemaking and conversation from getting too loud. If you’re smoking — tobacco or marijuana — others can smell it too. Marijuana may be legal in California and some other states, but it isn’t on a ship. And if you take it on shore, you might end up in jail.

“Most of the rules on cruise ships are the same as what you might find at hotels and resorts on land,” McDaniel said. “When it comes down to it, you’re on vacation so sitting back and letting loose is important, but you don’t want to tarnish your trip by exceeding the limits and having to deal with the repercussions.”

You signed a lengthy contract before you set sail that outlined the things that aren’t permitted on board your ship. Next time you sail, take time to read the extensive fine print.

“By signing the contract, passengers acknowledge they’ve read and will adhere to the rules,” McDaniel said. “That said, it’s at the discretion of the crew on board as to what the punishment might be for illicit behavior.”

Even if you aren’t doing something illegal, you probably don’t want to spoil someone else’s vacation. Don’t have loud conversations as you walk down the hall to your cabin, don’t stomp around inside it and don’t jump on the bed. Cabin walls are thin.

You don’t want to wake the neighbors and suffer their stares and glares in the morning.

Some of these cautions are particularly important for parents, who need to remember to keep kids in tow. You can catch a break by letting them hang out at your ship’s kids’ club, but ultimately, they’re your responsibility. No one wants to go to sea with bratty kids.

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