I've never seen any video of himw orking out for us. All Joe D said during his press confernce is that he watched most of Arron's games from last season. I've actually heard that Chauncey played with him in an open run at UCLA and told Joe D about him. If this is the case, I think Joe needs to realize that he is the general manager, and Chauncey Billups is not a scout.
Teams draft players they don't work out all the time. Plus, pistons do have scouts that they rely on also.