I fetched this autograph personally at the FedCon 23.

RDA was signing all four days in a separate room. Due to my schedule I bought tickets for Sunday. The autograph session started at 12pm and when I arrived, the queue was already very long ...
At 1.30pm he was forced to leave for the Stargate photo-shoot and the fans still waiting got handed numbers with their position in the still very long queue. When I finally arrived, I was told not to ask or a personal dedication, not to shake hands and not to make any small talk. However, RDA insisted on chatting a bit with everyone and when it was my turn, he really liked my pictures. Naturally I told him how pleased I was and when he realized, that I made them myself, he jokingly offered me a job - but when I asked him how much he would pay and the answer was "not much" I declined ;)