When we were on vacation, one day we came back to the room after being out and about for a while, and my key card didn't work. So I went down and had it reprogrammed, and it worked fine again. Same thing happened the next day. It finally dawned on me that I had the card in the same pocket as my Mini - the magnet on the Mini was erasing the programming. So be sure to keep any such cards away from your mod.
