That's false. The one area where I'm sure google doesn't mess around is with their ads division. They spend a proportionately large amount of money combating fraud to prevent erosion of confidence and most importantly accuracy in their main money maker.
If you've ever taken a look at the number of conversions fb ads provides vs google ads, you'd know this.
Agreed, especially where most of these clicks can be carefully audited and reconciled by the advertiser, it would make no sense for Google to threaten its reputation and primary money maker.
Edit: that being said, this does not seem to hold for Facebook, and I don't have a good reason why.
If you've ever taken a look at the number of conversions fb ads provides vs google ads, you'd know this.