The other day we reported on Google testing AdWords at Bottom of Google SERPs. Yesterday afternoon, a WebmasterWorld thread member reported Adwords at bottom of SERPS bug. Where some of the ads at the bottom, when clicked, were taking you to the wrong site. He reports that if you clicked on the URL itself, it took you to the correct place, but if you clicked on the ad title or description, it took you to the wrong place.
Problem is, I can not test this, but if you see the Google Ads at the bottom for a search on click fraud detection, you should be able to "mouse over the text to the right of the link at the bottom, and you will be taken to a site listed in the blue Adwords box at the top of the screen instead."
Forum discussion at WebmasterWorld.