[notahacker]

It's difficult to "know" the source is suspicious when a fraud hotspot also receives $35 billion a year in remittance income from the same countries targeted by the fraud, and supplying a means for people to send income earned working in Western countries to various unbanked relatives and their creditors in small African towns is Western Union's raison d'etre. That doesn't mean they can't be more helpful in dealing with fraud and that no agent has ever suspected anything of any of their more regular customers, but sending a few hundred dollars to a Nigerian is a standard legitimate use case for Western Union.

[coryfklein]

As the article points out, Western Union actually knew that some specific transactions were fraudulent, but did nothing to report or prevent them.