[bradk]

you really should read Disney's PhotoPass - September 2008 as recommended above. it reads in part:

Part of the genius of the system is that there is no limit to how many cards you can have and combine at a later time. That means if your group separates, each group can have its own card to be added to everyone else's later on. Also, should you forget the card in the room or lose it (glad you wrote the number down now?), you can ask for a new card. Speaking from personal experience, sometimes it's easier to just ask for a new card than dig through a deep and over-stuffed cargo pants pocket. Some guests have been known to use their cards for multiple trips, but it's completely unnecessary and in fact might cause an unforeseen issue as changes are made to the system.