Your cruise can take a year to save for ...
... and only a second to ruin.
I love the suggestion that a shipwreck would simply ruin the cruise experience -- as if it were just a big inconvenience, no worse than bad weather, or an outbreak of a shipwide illness, or the lido deck being closed for the entire voyage.
Don't you think that if you were on a cruise, and the entire ship sank to the bottom of the ocean, you'd have bigger issues to deal with than trying to get some kind of refund for your tickets?
Personally, I'd be more concerned with surviving -- and avoiding the sharks.