A WebmasterWorld thread named Use of URL redirectors in MFA ads discovers that some MFAs (Made For Google AdSense Sites) have been using redirects to bypass any blacklist the site may be listed on. What happens is that they will advertise using a URL of a public URL redirect tool, and the ads will get through the URL filters. So now you need to follow and continue to block these types of URLs. Let me explain a bit better....
URL: www.mfa.biz (fictitious URL) is a site on my filter list Owner of MFA.biz sets up a redirect URL with, let's say tinyurl.com, to point to MFA.biz TinyURL.com is not on my filter list and passes through the filter
What needs to be done? Well, Google needs to check for these redirects and not allow it, period.
Want to see the frustration of some Google AdSense publishers? Visit the thread at WebmasterWorld.