I’m unfamiliar with how Google Video Partners works, but how could anyone go about randomly sampling the sites their ads are running on? According to the article Google won’t tell you where your ads are running. And just finding shady video websites is also not an unbiased method.
Also just to be clear, clicks are not likely to be randomly distributed between legitimate and spam sites. If advertisers are paying for plays, they need to be able to see that information as well.
If I was spending money on video ads now I would be somewhere between cancelling my ad spend and calling a lawyer.