In 2015, 27 people fell or jumped overboard from cruise ships, which is the highest number this decade.
Given the fact that nearly 22 million people took a cruise last year, the fact that around 27 fell or jumped overboard, means that it happens to only around one person per million cruisers. So although it is in effect only a small number it is still sufficiently high to cause concern. In addition the numbers could indeed be higher than those which have been reported.
It is very difficult to fall off a cruise ship accidentally, and it is thought that alcohol often plays a major role. But given so few people survive it is often very hard to know the reason that the person went overboard. A woman who fell off the Carnival Destiny in 2012, and was rescued, confirmed that she was very intoxicated at the time and later suggested that her inebriation played a role in her having fallen overboard.
Often when it is not known if alcohol was a factor, some people fall overboard after making rash decisions such as trying to climb over railings or jump off balconies following an argument, usually with their partner.
If you drink on a cruise ship it impairs judgment and reduces the element of fear which leads to a tendency to carry out risky activities people would not normally indulge in. Alcohol can also make depression worse, so those who are already depressed can be tipped over the edge to becoming suicidal.
Those cases which are not alcohol related are often never solved and can indeed be a result of foul play. However they are often classified as suicides as there are no witnesses and the cruise lines are not always open to passing on information which might not be in their best interests. In addition the cruise lines do not carry specialists on board to secure potential crime scenes and gather evidence in a professional manner.
For those who do fall or jump overboard, the chances of survival are not good, being around one in five, as many do not survive the initial impact with the water and drown, or they die of hypothermia, are run over by a passing ship or are eaten by sharks. In order to maximize chances of survival, try and float and expend as little energy as possible.
The cruise lines could do more by increasing the height of some railings and use man overboard technology to pinpoint exactly when and where someone fell into the water. Also, the cruise lines could try somewhat harder to curb excess alcohol consumption to reduce passengers from becoming a danger to themselves.