Via DigitalPoint Forums an Google AdSense publisher reported that his publisher ID, the ID that tells Google who to pay for ads on a site, has been changed without his knowledge. The publisher says that he logged into his account and saw zero impressions, so he reviewed the ad code and noticed that the publisher ID was not his own. He suspects someone hacked into his server and changed the publisher ID (pub_id) within the code.
This is the first time I have seen this posted in a forum. So beware of more scams like this.
Forum discussion at DigitalPoint Forums.