Several times someone has come to visit us for a few days and all we had to do was inform the front desk and go pick up an extra key and parking pass.
One time, at BWV, DH and I arrived 2 days before DD and BIL. (No dining plan) We didn't have them on the reservation. When we went to add them, they had to give us ALL new keys. It was bit problematic, because when DH went to get the keys for them, I was off somehwere else. We had to go to the desk together to insure that neither of us was walking around with a cancelled key.