Glenn Reynolds notes, this morning: 
HECKLE AND CHIDE: When bus passengers yell at driver, it improves safety.  Is this an argument for free speech in general?
Well, consider this question in light of the actions of the federal government and the tea parties… the latter of which are engaged in as classic an example of free speech as we’ll ever see in our lifetimes. Do you suppose that in the end, it’ll keep Obama and the Congress from going even more radical leftist than they might have?
That’s a thought that is both encouraging and frightening at the same time. Frightening, to contemplate just how far they’d go absent that very vocal check on their power.