I will have more to say about this, but I have just learned that Helen Immelt, the Washington woman who challenged her conviction for horn-honking on First Amendment grounds, has been vindicated by the Washington Supreme Court. See "No Right to Honk, Judge Tells Chicken Lady," Lowering the Bar (June 10, 2009); "Washington Honking Case Taken Up by State Supreme Court," Lowering the Bar (Nov. 12, 2009).
It appears that the majority ruled, six to three, that the state statute under which Ms. Immelt was prosecuted was overbroad, and so it did not decide whether her particular honking conduct would constitute protected speech. Two dissenting opinions - one longer than the majority - argued that the statute could be construed more narrowly and that the nature of the conduct was relevant, but obviously they did not prevail.
I previously referred to Ms. Immelt (in that headline, at least) as the "Chicken Lady" because the honking was reportedly in response to a neighbor's complaints about the chickens she was keeping in her yard. Especially now that she's won, it seems more appropriate to refer to her as the "Victorious Washington Horn-Honker" or maybe just "Ms. Immelt," so that's what I've done here. Either way, congratulations are in order.