This reminds me of a story that appeared in a magazine some years ago. I think it was Playboy. There was a full page story about Jerry Falwell, the lunatic fringe evangelical televangelist, having sex with his mother in an outhouse. It even had cartoon pictures of the outhouse with a half moon on the door.  Falwell and his church sued the publication (or was it Larry Flynt the publisher). The story was so off the wall and funny that no one would possibly believe it. 
The judge asked Flynt's lawyer if he believed the story and the lawyer said of course not. He then asked if he knew anyone else who believed the story and got the same answer. And, that was the end of the trial. I don't remember if Flynt then sued Falwell but he probably did. Does anyone remember any more of the details about the story or have any corrections? It was a long time ago.