[kaendfinger]

The "fire" in a movie theater argument is a horse than has been beaten to death for so long, and I seriously doubt anyone who says this phrase knows it's history, or even cares to think for themselves about how much of a cliche it is.

[chiefalchemist]

The point is, cliche or not, not all speech is 100% protected 100% of the time. That myth is bigger than the fire myth is cliche.