That is a great response and true. What these researchers are proposing does not match the usual meaning of click fraud.

Though the harms it causes are similar:

* advertiser is paying for clicks/impressions from a bot rather than a user

* publisher/network sending lower quality traffic to advertiser faces reputation and financial risk

Likewise, depending on the situation fake social media profiles also can harm the quality of said network.

In terms of damages caused by the researchers' action... clicks would be the most harmful. Especially against insurance, loans, and mortgages which they seem to be interested in. Those have some of the highest CPCs around. (e.g. http://www.wordstream.com/articles/most-expensive-keywords)

Isn't that what most click fraud is, though? Paying someone/something to click your own ads? Who would do click fraud if they aren't somehow being compensated by the ad provider?

"Unrelated third party" is presumably a party that is not being paid by the beneficiary of ad revenue.

Right. But my question is... why would an unrelated third party engage in click fraud? All I can think of is some kind of framing, in an attempt to get a site owner delisted or sued.