I would think that customers are reasonably sophisticated when it comes to stuff like this, particularly when they are spending real $$$.  How difficult is it, for something like brand advertising, to do before&#x2F;after poll&#x27;s to discern how effective the dollar spend is in promoting a brand (with conversion to sales, it&#x27;s even more trivial.)<p>Done properly, the customer doesn&#x27;t actually care if 99% of the exchange inventory and impressions are fraudulent, as long as they accomplish whatever objectives they set out to.<p>Put more explicitly, if the objective for an advertiser (or, more likely, their agency) is to build awareness of a brand, they can measure a measure awareness among their target group, run a few million dollars of advertising, and then measure awareness again to see the difference.  Done with enough customers, and enough programs, you start to get a very clear sense of where the dollar is best spent.