I guess Google would be the one's you'd expect to say there is no click fraud, or that there's so little fraud (try 0.02%) that it's not worth suing us ….or don't get your hopes up when you sue Google for Click Fraud - this comes from SearchEngineLand.  Here's 5 definitions:

"…

• Invalid Clicks: This is a Google term. It means that of ALL the clicks Google ads generate, a percentage of these are deemed "invalid." These are clicks that Google makes no money from. It either never bills for invalid clicks or eventually issues a refund. Not all invalid clicks are necessarily fraudulent (such as in cases of quick double-clicks that aren't billed).
   
• Fraudulent Clicks: These are the percentage of clicks that an advertiser is charged for when the person (or bot) clicking is doing so to purposely cost the advertiser money or make money for themselves through an ad program.
   
• Overall Click Fraud Rate: This is the number of fraudulent clicks as a percentage of ALL clicks that happen, regardless of whether Google issues a refund or doesn't bill.
   
• Detected Click Fraud Rate: This is the number of fraudulent clicks as a percentage of ALL clicks that happen where Google generates a refund after performing a requested or "reactive" investigation asked for by an advertiser. Google would call this the "re actively identified invalid click" rate.
   
• Undetected Click Fraud Rate: This is the number of fraudulent clicks as a percentage of ALL clicks that happen where no refund has happened because neither Google or the advertiser spotted the fraud.

But it's all in how Click Fraud is defined.  If 30% of the clicks are fraudulent but Google detects it and prevent the fraud from applying to your account - then they say there are little or now Click Fraud.

Honestly, I don't know ….. but 0.02% seems awfully low.