Western Union has paid fines on 1 or 2 occasions for AML deficiencies by it's agents.
I'm sure they are on their way to paying many more fines, judging by how rampant people are using Western Union to defraud people of money on many internet and social media sites. Just go to Instagram and search for the hashtag #flipmoney and see how many people are openly bragging about being Western Union agents that can help process cash transfers on behalf of other scammers, for a fee (that is most likely higher than and on top of whatever fee Western Union actually charges). These people are have no fear of being caught whatsoever.