BoingBoing points to the story of a librarian who got a $500 fine for "ethics violation" after promoting his daughter's book in the newsletter, and by distributing free copies. (He called it "Best Book Ever", hence the title :))
Just so happens that the book in question is a Manga version of Macbeth. Hey, I'll take popularity for the bard anyway I can get it. If people buy copies of the book just for protest, that's still exposure!