I disagree. Bob I'm sure chose to put this on "the set list" for whatever reason he had. He could have picked any song or musical jam outro but instead chose Tom Thumbs Blues. Because of that I think it should be included as a song on the set list. Even more so because this was not a one off (this song was played a few times) and it is clear and distinct even without the words. What a treat to hear his band play this song. It's one of my favorites.
Also, he played dignity last night! I can't stop smiling still