RCI requires legal docs for 2 reasons, [a] - if your surname is Jones and your children have the surname of Smith they need birth certificate to prove that Ms Jones is the parent of the Smith children; or if Mrs Smith has divorced and then remarried a Mr Jones, they will need the trail of birth certificate, divorce cert and marriage cert to show the name trail that it is the same person. [b] if you are taking someone elses chiild on holiday or your grandchild you need a legally notarised letter from the childs parents giving you permission to do so and giving you permission to sign waver forms and giving you permission to authorise any medical treatment.
Wow!! Thank goodness I'm not divorced . I could't be bothered with all that hassle for a holiday.
Are you referring to a legal document required by the cruise company? If a sole parent wishes to take their child/children out of the country, some holiday companies will require a witnessed signed letter from the remaining parent to say they approve of the arrangements. This often happens when the children have a different surname. Apologies if I'm barking up the wrong tree. Perhaps someone from the legal profession has a definitive answer.