Q-PKI regulation by consensus?

One regulation many might agree on for crypto-currencies is a limit above which quantum-key-exchange security should be used. For example - all transactions involving more than 20k in value ( assessed by a basket of leading currencies )  Risky transactions might then be identified early and consumers warned that state-of-the-art security was not assured.  Some large losses might be capped this way.  Even if it could be harder to get consensus about than C02 emissions.