This eweek article mentions a proposed class action against Google by one Samuel Lasoff. He seems to be an advertiser but the article talks about aggrieved publishers:
"and accuses Google of exposing publishers to click fraud following a breach of contract,"I can't find the original filing in the PA courthouse (what a quaint, 1990s web site!) so I can't tell if he is a publisher or advertiser. He certainly appears to be an affiliate, so I suspect he had Adwords pointing to his sites.
Let's see what happens.