When staying at a Disney resort, inquire at Guest Services regarding the celebration cards. They could have the autographed Princesses card waiting in your room after a day in the parks. During birthday and anniversary trips, a little Disney elf always seemed to leave "something" in our room (this was without asking though.) I think being in their Disney system so long, they have the information flagged now.
Even during one trip, our youngest became ill and they sent a celebration card with some balloons to cheer him up. Very sweet gesture!