basic "due diligence" is what is needed to see the fraud and do something about it
How To Find Bot Traffic With Google Analytics
less than 50% of an advertiser's dollar goes to "working media" (showing digital ads) when they buy through the long, complex, and non-transparent programmatic supply chain
How Much Of Your Dollar Goes To Working Media In Digital?“
that's not even taking into account how crappy targeting is (because it's all derived data)
How Accurate Is Programmatic Ad Targeting?
or the activity of bots (bots pretending to be any audience segment you want to target)
Bots Emulate Any Audience You Want To Target—Here’s How