If by modern financial and legal infra-structure you mean things like stocks, futures, and derivatives, then I don't think I agree. The modern infrastructure in

If by modern financial and legal infra-structure you mean things like stocks, futures, and derivatives, then I don't think I agree. The modern infrastructure insulates two parties in any transaction with brokers and exchanges. For example, if the "losing" party on an options trade can't pay up, the exchange pays for them. The exchanges and brokers set margin requirements to reduce the risk of non-payers.