It is amazing when you see a webmaster using a blogspot blog stealing an AdSense Java Script Code and using it on their website. They will usually keep your unique publisher ID while showing ads from your account. While their action may be unintentional in terms of them not caring which ID that they use, the net effect is that you are now involved in their illegal action.
Whatever their reason for doing so, once they are caught and banned for using illegal and plagiarized materials, chances are that Google will also ban your Adsense account as well because it violates the terms of service and the program polices even though you may not have been aware that this happened to you. It doesn't really matter to Google because they see your unique publisher ID and assume that it is you posting the illegal materials.
In addition, there are websites that also use the iFrame HTML program that will embed to the post and pages of your website as well. This means that you are now violating the Terms of Services as well as the Program Policies because they are showing the AdSense ads inside an iFrame which is forbidden. Again, because it is your website, Google will assume that it is you unless you can take appropriate action.
While this may seem unfair, it must be noted that Google has recognized the practices of others in using the websites and unique publisher ID, so they have developed a new feature called "Access and Authorization" that you can find within the dashboard of AdSense. It is here that you can only allow certain sites to show ads for your account and not have to worry about getting punished for something that you did not do.
