A friend and I did this last year and what a mess!! The printout from the FD did not separate it out so you had to add each persons tab up. They were finally to at least tell us what was on what card and we both paid our charges before we checked out or at least we thought so. About a month after we returned home i got a statement in the mail from Disney so i opened it not realizing it was my friend's statement. It had her name and my address i'm assuming because the reservation was under me and my address but her address is in their system too, she goes more often than i do. It showed all her charges still open at about $500.00! I gave her the statement and she called Disney, they looked into it and said she was all set. Another month goes by and another statement, this went on for about 10 months. She called every month and they told her the same thing each time, all set. Finally she blasted them and the statements finally stopped. She had proof the bill was paid. This situation has made me nervous about our upcoming trip. I don't want another problem like this with 6 of us. However i think it would only be my family on one card and my sister on her own. We'll see what happens. It's nice not to have to bring a lot of cash to the parks.
p.s. if you forget your pin, do you reset it at check in? I didn't see where i can reset it on MDE.