I have. The US government ultimately is the final guarantor of the loan. If no one else pays the US government will. It is simply a mechanism to lower borrowing costs to the borrower which subsidizes the sale by the manufacturer. Just like Freddie and Fannie and ultimately will end the same.
In this event, the US has recourse via sovereign debt to the government of the borrower’s country. Are you saying that the US would simply write it off? I don’t think so.