Double Reservations question

[ratfam]

Hi, for our upcoming 8 night trip I currently have booked two dinner reservations each for the last two nights. I was going to wait until we had more specific info about our Magical Express departure time, since we leave for the airport on the last night, then decide which to keep and cancel the others. The CM that helped me said that if there is a system audit the double reservations could be picked up and we would be cancelled out. From reading these boards I thought that double reservations is pretty common. Any thoughts as to whether I'm likely to have a problem? Thanks.