Groan...not again...
You ARE free to yell "fire" in a crowded theater. The government does not require a license to do so, does not explicitly forbid doing so, and does not tax/regulate/prohibit any tools that facilitate doing so.
If there IS a fire, nobody will question the legality of you shouting "fire".
If yelling "fire" is part of the performance and is understood to be such, no harm will be done.
If there isn't, and harm is done by you doing so, the issue isn't that you violated a restriction on yelling "fire", but instead are responsible/liable for the consequences of your actions.
Lose the tired, inaccurate, ignorant analogy already.
I think you said that better than I did. Kudos! ;-)