You provide the incentives to the countries to fix their problem by cutting them completely off. If someone using a bank in Cyprus did it, you tell Cyprus government that in 48 hours the Fed will block all transactions with that bank and you block it. They move to another bank, you repeat it. Eventually Cyprus government ( and Cyprus banks ) have to make a choice - continue to tolerate scammers using their banks and be locked out totally out of the US financial system or crack down on the scammers.