Not that I disagree with your premise, but an issue with this is that people like to see punishment that fits the crime - I'd expect public outrage over a misdemeanor prosecution for an infraction that may result in loss of life.If someone got stomped to death in a stampede triggered by someone's cry of "fire", methinks the person or people who did the stomping would have a lot to answer for. You shouldn't do that even in a real fire. The only difficulty is that it may be hard to identify the culprit(s) if everyone was busy panicking about their own escape routes; and I can see how a mob, with no other targets available, might place all blame on the original "fire"-shouter.
But perhaps this "loss of life" thing is an incidental flourish, and your main point is that people, responding legitimately to a fire alarm (not stomping on people), suffer a lot of inconvenience (they drop whatever they're doing and evacuate), and the "fire"-shouter is responsible for all that and perhaps should pay for it. I agree with that. I don't see a problem with assigning a large punishment to the simple crime of trespass when the trespass has large consequences.
Suppose I gain access to a Toyota plant and press a few buttons or rearrange a few materials in such a way that a batch of several cars comes out ruined. I haven't done anything beyond simple trespassing, but I am responsible for thousands of dollars of property damage, and I can be made to pay for it, right?
So either this is a case where a trespass is a huge crime; or I can be considered responsible for massive property destruction, even though I just pressed some buttons or rearranged stuff (possibly without realizing the implications of my actions), and even though it required the actions of other people in the assembly line to completely carry out the destruction. (In the latter case, what makes me guilty and the others innocent is that I committed a crime--trespass--and they didn't.) These choices seem largely equivalent to me; the former has the drawback that you can no longer hear "trespass" and think "Oh, ah, trespass, a misdemeanor, with maximum punishment X", but perhaps this could be remedied by calling it "trespass causing major property damage". Either way, I think something similar could be made to apply to the case of a false fire alarm.
Those fines are actually due to local ordinances. As such they are an example of government imposition on individual freedom in order to protect the public, and are a bit of a counter-example to your point.
Interesting. I didn't know that. Still, couldn't you call it a form of trespass and still punish it with a fine of approximately that magnitude (see above for further discussion)?