Re: Best Show etiquette breach, I think at this point in the show's history, a guest mentioning "Jon Wurster," especially in the context of him being a drummer in the "real world" -- which he is! -- barely registers. In the case of Nardwuar, he did make a reference to JW being Tom's "co-host," but he was basically just trying to determine if JW played drums with A.C. Newman* on the John McEnroe program.
*He didn't. Carl chose Tico Torres for that performance.