Tiggers, trust me, I was freaking out just like you, so I brought it. NO ONE ever asked to see it. I would assume that if you maybe used your maiden name for some things and your married name for others you might need it, and your child might if their last name were different. But it was me and the hubby and the DD all the same last name. Remember to bring your license as well as each birth certificate. They did look at the picture ID. But don't stress, you will not need the marriage certificate. I was going to get passports too, but why spend all that money if you don't have to? I just kept all the important papers in a ziploc, in the nice little travel folder thingy my TA gave me and then locked it away in the safe when I got to the room. When we got off the ship, we only needed our KTWC and our licenses. The only time you'll have to take the Certificates out again is when you have to go to customs. Have a wonderful, wonderful time.