Recently, someone copied the Adsense code of this blog and pasted it on a porn website. As the entire Adsense Javascript code was copied across including the Adsense Publisher ID, Google got the impression that the offending site that violated Adsense TOS was also owned by me.
I quickly received this warning email from the Google Adsense Team:
While reviewing your account, we noticed that you are currently displaying Google ads in a manner that is not compliant with our policies. For instance, we found violations of AdSense policies on pages such as site_url_removed.While this is just a warning email and you still get ads on other sites, the point to note is that you still run the risk of getting banned if similar violations are found in future. [something not in your control]
As stated in our program policies, AdSense publishers are not permitted to place Google ads on pages with adult or mature content. As a result, we have disabled ad serving to the site.
Your AdSense account remains active. However, we strongly suggest that you take the time to review our program policies to ensure that all of your remaining pages are in compliance.
Please note that we may disable your account if further violations are found in the future.
So I sent back an email to Google clarifying the things and few hours later, received the following email from Google AdSense Policy Enforcement team.
We request no further action from you at this time. If you find any other sites that are using your ad code, or if you receive additional notifications regarding violations on sites that you do not own or maintain, please reply to this email and we'll be happy to investigate the matter.This email from Google was definitely a big relief.
Unfortunately, there's no way to find more violations yourself because search engines won't help you find text inside the HTML source. So even if you google your Adsense ID, it won't help much unless someone develops an HTML code search engine.
Now if you have similar concerns and like to be on the safe side, I would suggest that you send an email to Google specifying a list of websites where you are showing the ads. If they know of other websites displaying Google Ads with your publisher id, you may as well ask Google to disable serving ads on sites/blogs not owned by you.
Related: How to Test Different Ad Layouts