I am in the same position as Queen of Diamonds above, I have been traveling with my grandson on land and sea vacations since he was 5 years old and always carry an updated, notarized, permission letter with me regardless of where I travel. Both Carnival and Royal Caribbean have asked me for the letter. Royal Caribbean copied it and Carnival just checked to make sure I had it. If there is a medical emergency involving your child or grandchild, the letter is sufficient authorization to allow you to make immediate decisions regarding treatment. My bank offers notary services free to bank customers and so does AAA Travel.