Yesterday, we reported that Google changed their AdSense program policies but focused on the fact that Google is disallowing ad rotations of some type. But I missed something highlighted by a WebmasterWorld thread that shows Google making it more strict on content scrapers.
Website publishers may not display Google ads on web pages with content protected by copyright law unless they have the necessary legal rights to display that content. Please see our DMCA policy for more information.
Google's DMCA policy is at http://www.google.com/adsense_dmca.html.
Honestly, they have always request that AdSense publishers use the DMCA request to stop scrapers, but I guess now they made it clearer in the program policies.
Forum discussion at WebmasterWorld.