Obey (my misreading of copyright law)

Many of you have seen the work of Shepard Fairey. His Andre the Giant images are iconic in underground art. He seems to be a better artist than copyright lawyer though. He recently sent a cease and desist letter to an artist who has taken to parodying his style. This is exceptionally ironic as Fairey has himself been known to borrow a design element (or entire concept). Considering there is an exception to copyright law for parodies, I’m guessing this won’t go anywhere.