Trying to catch up on cases I haven't read yet and ran across U.S. v. Reed which is your (sadly) fairly typical case where some yahoo files liens on everybody who has irked him. The interesting part wasn't that. The interesting part was reading that the IRS has a Frivolous Return Unit.
You have to wonder what sort of silliness these folks deal with every day. Do you think they have different sections? The biggest would have to be sovran citizens. What else do you figure they face? People who are getting instructions from space aliens or ghosts? Equiring minds want to know.