I once read a story of a teenager traveling with his family by car to board a cruise ship. When the group arrived at the ship for embarkation, the poor kid was not allowed to board because his passport had been packed in his checked luggage already aboard the ship. Sometimes passports and ID are checked at the outside gate to the terminal, where one could have the opportunity to retrieve their passport before boarding. Apparently, in this case passports were not checked until the family were inside the terminal and the luggage was well on its way to that vast sea of baggage on board. While I don't remember the exact ending to this unfortunate occurrence, I do recall that it was impossible for the cruise line to locate the luggage and passport prior to the ship departing, and the teen was forced to stay behind at embarkation.
Most of us who have some experience traveling know the importance of keeping what's most important close to us - whether it be a vacation by land or by cruise ship. But for some folks not accustomed to traveling, these facts might not be so apparent. It's important, especially, to remind teens and young people who may be traveling with friends, with a school group or even with the family to make sure they have the documents necessary for boarding aircraft and cruise ships and to make sure they have these documents with them at all times.
One of the best things you can do to prepare for your cruise is to make two packing lists: one for your checked luggage and one for your carry-on bag. Do a double-check before you leave home. Valuables, important papers, ID, passport, boarding passes, and medications should always be brought on board in your carry-on bag. To go one step further, your most important piece of paper - your passport - should be kept directly on your person.
For further details on what not to pack in your checked luggage, read the accompanying article: What NOT to Pack in Your Checked Luggage