I love the BS that Twitter tells you about the ROI of their ads. "70% of people who follow you will buy from you".. DUH... That's because the people who follow you are for the most part your EXISTING customers. The other 30% of course are bots.
The Google engineers are also trying to release their methods. This is not detecting 'fraudulent' activity, but rather trying to classify adversarial advertisements: http://research.google.com/pubs/pub37195.html (pdf is linked there). You can assume that they are doing the same types of thing to classify fraud.
The reality is this: everything in this video is 100% true and it's been this way almost since the beginning. But most marketers are just checking a box. No one really cares about the budget spent on social ads. It's a line item next to display and TV.
I should say, this isn't just true with Facebook. The same thing happens on Twitter and YouTube. Google AdSense its he only platform that even attempts to sniff out fraud. No one else even tries, because no one cares.