At Strata (O'Reilly's BigData conference), there was an entire session track dedicated to fraud prevention and legal movement on this type of stuff. Although, you will never be able to stop this (unless you stop people from being driven by money) the data community is taking this kind of detection very seriously. Every business, if it get large enough, is going to care about this type of fraud, if only to pay it some amount of lip service

I saw a presentation. From a data scientist at bitly. She showed that spammer links have a distinctive traffic shape (constant over time) while real links have a totally different one (initial peak followed by logarithmic drop to zero). Similar patterns exist in advertising campaigns. 6MM/month seems like a lot of breakage that someone is fine cutting that check.