Given that even Wikipedia effectively restates what he says, I'm pretty sure he's correct here:

> Ultimately, whether it is legal in the United States to falsely shout "fire" in a theater depends on the circumstances in which it is done and the consequences of doing it. The act of shouting "fire" when there are no reasonable grounds for believing one exists is not in itself a crime, and nor would it be rendered a crime merely by having been carried out inside a theatre, crowded or otherwise. If it causes a stampede and someone is killed as a result, then the act could amount to a crime, such as involuntary manslaughter, assuming the other elements of that crime are made out. Similarly, state laws such as Colorado Revised Statute § 18-8-111 classify knowingly "false reporting of an emergency," including false alarms of fire, as a misdemeanor if the occupants of the building are caused to be evacuated or displaced, and a felony if the emergency response results in the serious bodily injury or death of another person.[16] Somewhat more trivially, in some states it is a crime just to knowingly make a false report - or knowingly cause a false report to be made - of an emergency to emergency services.[16] In Colorado it is a crime to knowingly cause "a false alarm of fire" to be transmitted to "any...government agency which deals with emergencies involving danger to life or property."[16] This crime could plausibly be made out where, for instance, in response to the false shout, an innocent bystander calls emergency services to report the fire, and this is found to have been such a foreseeable response to the shouts that the shouter is deemed to have caused the false report to be made.

Whether those laws actually survive the Brandenburg test is untested, from my understanding. But given that potential first amendment violations are held to strict scrutiny, I question whether the government could actually pass the imminent lawless action test even had someone did it knowing it would cause a panic, and would need to try with some other offense.