John Dillinger had a lousy credit rating too, but banks seemed to be willing to let him have some money anyway. And for pretty much the same reason.
On the other hand, why would anyone still have money of any type in a Zimbabwe bank? Was it impossible to withraw it and get it out of the country (or at least buried somewhere) in the past ten year?
As long as they are a "legitimate government", they might even be able to access accounts held in foreign banks by their citizens.
What would stop them ? Would a US bank, or a French bank honor a "legal" court order from Zimbabwe to place an account held by a Zimbabwe national into some sort of "escrow" status where Zimbabwe could borrow from it ?
I don't know the answer. But it makes you wonder about the fading banking secrecy laws, doesn't it ? At the rate the world is eliminating them, whatever nationality you are, your mother country (and a host of their treaty partners, probably) will be able to find it and get their grubby hands on it.