I thought I was the only one! I keep a 5x7 index card in my park bag with all of our conf#'s on it and another in the room just in case. I found that putting them on the index card keeps them from getting a tattered by the end of the trip. You are right , they were very suprised that I had that info.
I write very small anyway, so I write all my ADRs on a Home Depot lime green Mickey Head, cut them out, glue two heads back to back, then laminate them, poke a hole in one ear, attach a rubber luggage tag holder thingy and then attach the LGMHs to my park bag. Even if I'm on the DxDDP I write small enough to get all my ADRs on there (front and back). It identifies me as a DISer and I always have all my ADR numbers and times handy. It's waterproof and never gets tattered.