[mrguyorama]

In that case, wouldn't it be more that it isn't allowed to yell fire in a crowded theater with the express purpose to cause injury during a stampede? Would doing so "just as a prank bro" still be protected under American precedent?

[rosser]

I'm not a Constitutional or 1A scholar, but I believe the test remains whether the speech is substantially likely to result in "imminent lawless action". Whether you wanted people to get trampled, or just thought it was a lulz thing to do, exigently emptying a crowded room on false pretenses is probably going to yield some pretty lawless behavior.

EDIT: Even so, that test was IIRC conceived as a means of measuring whether political speech — specifically, advocating the use of force or criminal behavior — was 1A-protected, so I really wonder whether this line of thought isn't moot.