That's another sour old lemon. Ollie Wendell was one smart fella, but he was dead wrong on that one. There's no such limitation on the right of free speech. The real problem with shouting "fire" in a movie theater is that the theater is private property. When you buy a ticket and enter, you're making an implicit contract not to disrupt the show, and you're in breach of that contract if you shout "fire". It's all about private property rights.
(Due credit to Walter Block and "Defending the Undefendable")
You know. I never thought of it like that. Thanks for the new slant.