I don't think so. I have several web sites with AdSense on them. This morning, one of them has an very high percentage of clicks on it for today:
So what's the incentive to report this to Google? For me, I suppose it's simply the right thing to do. I'd like to say: "I think there's click fraud happening here." However, I can't find any place on the AdSense publisher UI that says how to report it.
So I guess I can send the info to the "contact us" email. But if Google were serious about preventing click fraud in AdSense, I'd think they'd add an incentive and an obvious way for publishers to flag it.