> I suspect the majority would do the opposite and deny/understate the problem.
I don't know. I've seen so much fear-mongering in my life. We're all going to die from zika, n1h1, ebola, killer bees, aids, mrsa, terrorists, and so on. In each case, there's something to be afraid of, and you might actually know someone who died in one those ways, but the media and the lay people blow it way out of proportion. The people I've know who died have been from drugs, suicide, heart failure, stroke, and car accidents.
> The sensible thing to do in the absence of information is precisely to imagine the worst outcomes and act with them in mind.
I can't accept that as sensible. It's easy to contrive unacceptable courses of action by applying that rule: "The police don't know who the murderers are, so they lock up everyone to avoid the worst outcome." "The doctor isn't sure how bad the infection is, so we amputate all the limbs just in case."