I found this in a Warrior Forum Thread. What the user has done is removing the Publisher ID in AdSense code for couple of days and replacing it after that. What he has gained is a high increase in earning-per-click. As he says,

“As you all know, there is a “publisher id” that Google AdSense provides you. As some of you might have experienced before, once you delete the publisher id, the ads will keep being shown on the site, but you will be publishing them for no cost by Google’s side.”

“I did a test about this, and the result was great. I removed the publisher id. The first 2-3 days, AdSense spider almost never left my site (the same site we’re talking about here, before with publisher id, and after without publisher id). The following 9 days, the spider never came to the site though. But guess what this test taught me? After I removed my publisher id for 2-3 days, when I put my publisher code again my eCPM was as high as $1,2. I was getting $1,2 per click and the ads shown were high paying ones instead of those crappy ones. That was an amazing experience for me.”

The reason I can think of is the Google’s Quality Score over other sites. As stated, by removing Publisher ID, if Google tends to show its ads, then they surely should be high paying ads since anyone would have to pay high to show an ad on Google’s own network. What has been left is the same quality score to the publisher after he replacing his ID.

In my opinion, Google Bot will catch this now or later and will replace previous rates, or may be not if the publisher remains lucky. An attaching problem which is also discussed in the thread is whether this breaks Google’s TOS on Ad Code, as Google says,

“Our program policies do not permit the modification of the AdSense code. Your publisher account offers a number of options when generating the ad code, that we hope will allow you to create an ad layout that fits in with your site. Please paste the AdSense ad code into your web pages without making any modifications.”

Does Google only care about the layout here? If you are not modifying the way ads appear, is it ok to change the code? Changing the Publisher ID has not been an issue to Google in the past since some AdSense revenue sharing forums and blogs already exist. Anyway you have to follow these kinds of tricks with extreme care. If your account gets banned, it’s all gone.