Actually I live between the US and Belize and have bank accounts in both countries. I understand only too well, what is going on. Like real life in the real world understanding not computer jockey understanding. The fact that the US banks decide it is easier to cut adrift the small, not very profitable, banking systems in the Carribbean than to clean up their own systems is what it is all about. The US government cannot make the banks reinstate the correspondence banking, as the US banks are "private companies" So these Privat companies can just stop the trade rather than clean up their own acts which they fear would cost them money, if/when they get caught not following the rules.
The fact now one often has to carry large amounts of cash internationally to pay large bills for builders and business transactions and then personally declare the amount at customs when entering these small countries, actually makes it far more difficult to keep track of cash movements than following a paper trail of bank transactions.
This still is off topic for a thread on additional airport security. Having nothing to do with remmitances.