In fact, I believe I was sunk by just such a well-wisher. I don't have any proof, because Google refuses to disclose any details about the nature of the "invalid clicks".
What I think happened: I was at a coffee shop, moderating a poetry forum I used to run. Someone watching over my shoulder asked about the site. I told them I ran it, gave them the URL. Later that day, I noticed that an unusually high number of ads were clicked on that site.
I thought nothing of it. Google supposedly filters out repeated clicks (or so I thought). I expected an automatic correction. However, the very next day I got the infamous "invalid clicks" email, and was permanently disqualified from any future participation in the Adsense program.
However, the ads continued to run!! I wasn't earning any income from them, but Google certainly was. That strikes me as shady, SO, I removed all ads from the site, and permanently disqualified Google from publishing any ads on any of my sites. :)
tgreer
Made Her Cry
2,118 posts since Dec 2004
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Solved Threads: 37