I think you'll find Ottoman and Austro-Hungarian finances were pretty shaky. Turkey was known as the "sick man of Europe" for a reason. U.S. T-bills would have been almost as good as the Bank of England :-) I'd point out that the UK defaulted (for some values of defaulted) in 1931-2 and stopped payments in forex on some war debts.
Mexico defaulted (kindasorta) in the 90s without having any more violence than Mexican politics tends to involve. Russia defaulted on the GKO bonds in 1998, without any more violence than post-Soviet politics tends to involve.
The astounding notion is that human beings are unbiased estimators of beans in a jar, having no significant directional error on the problem, yet with large variance. It implies that we tend to get the answer wrong but there's no systematic reason why. It requires that there be lots of errors that vary from individual to individual - and this is reliably true, enough so to keep most individuals from guessing the jar correctly. And yet there are no directional errors that everyone makes, or if there are, they cancel out very precisely in the average case, despite the large individual variations. Which is just plain odd. I find myself somewhat suspicious of the claim, and wonder whether other experiments that found less amazing accuracy were not as popularly reported.
This is precisely what I find disquieting about wisdom-of-crowds arguments - they require that our errors are nondirectional and normally distributed, but we know they aren't. We have cognitive biases!
It's a similar argument to my proposal of Rational Airways, an airline that asks you to sign a release when buying a ticket to the effect that you realise how tiny the risk of a terrorist attack is, and therefore are willing to travel with Rational, who do not apply any annoying security procedures.
The problem here is bias to one's own biases, I think. After all, we're all stupid some of the time, and realising this is surely a core component of the Overcoming Bias project. Robin Hanson may not think he'd ever be stupid enough to walk into the Banned Shop, but we all tend to assume we're the rational one.
You also need to consider the real-world conditions of your policy. Yes, this might be a good idea in its Platonic ideal form, but in practice, that actually doesn't tell us very much. As an argument against "regulation", I think, with a confidence value of 80, that it's worse than useless.
Why? In practice, you're not going to have "Banned Shops" with big signs on them. If enough people want to buy the banned products, and we know they do want them because their manufacturers are profitable, the rest of the retail trade will instantly start lobbying for the right to sell them, maybe on a Banned Shelf next to the eggs. That's an unrealistic example, but then it's an unrealistic proposal.
What's more likely is a case of Pareto inefficiency - if you relax, say, medicines control on the grounds that it's a step towards the ideal, the growth in ineffective, dangerous, or resistance-causing quackery is probably going to be a significant disbenefit.
"Perception and Misperception in International Politics" by Robert Jervis.