I guess because you have their birth certificates. But that is my argument, If I have to pay an adult price for my daughter who is 12 1/2 time of cruising then I feel she should be able to go into common grounds. If she is not considered a teen/adult for common grounds than I shouldn't have to pay an adjust price for her to cruise. I e-mailed Disney about my daughter going into common grounds and her answer was a big story, about how they did research of what age should do what activities, blah, blah, blah, with the outcome being that I had to ask a Program Manager about it when I get on the ship. I think they think that 12 year olds are still in grade school. But most are not, they are in Junior High. Sorry I got off the subject, I thinking maybe they have it written down somewhere. Curious?