I don't disagree with you, Craig, but consider that none of us live in a vaccuum. In a You Tube videos from the recent Small Favor signings called Originality (or something similiar to that) JB talks about how he *thought* he had this fabulous 'original' idea for Bob as a skull with glowing lights for eyes and he was so excited he'd come up with something so awesome that had never been done before... and then he sat down with his son and watched the opening sequence of Scooby Doo. Obviously, his unconscious nabbed the image and ran with it.
In the case with Bob, I think Jim saw a post Bob made here that likened Marcone to a Robber Baron of feudal times
, and used it as only JB can, expertly weaving the train of thought into the plot of Small Favor. While the idea itself pretty much is public domain, Jim had the class to mention to Bob after the fact that he'd swiped his idea cause he thought was a good one, and useful, and man, it made Bob's day!
Mind you, I think this is pretty much a unique scenario, (using a fan's idea) but I gotta give the man kudos for giving credit where it's due and never being arrogant or aloof about his talent.