Let me bring up another example so we don't get hung up on the issue the speech happens in a theater:
Suppose someone use his free speech (in a public medium, for instance a public park) to incite domestic terrorism. He quickly has a large following which he every weekend try to convince terrorism is just and right, i.e. he provide reasons for terrorism and explain how it should be carried out.
After a while, the number of terror attacks go up, and it is determined (for instance through interviews) the terrorists are inspired by this person and cite his ideas as why they carried out the attacks.
The person begin to note this in his speeches, and says it is a good and just thing, and intensify his calls for more terrorism.
I belive this would (and should!) constitute "banned speech" because of the (a) obvious and direct danger (b) he is aware of the danger and nevertheless persists. I therefore think the speech should be banned; i.e. his free speech should be limited.
Do you agree?