We\'ve been having an problem recently where other sites are running our e-commerce site inside a frameset where our site (with the offenders affiliate id tacked on) is the only
Take a look at this article. It offers a fairly simple solution for detecting frames and breaking out of them.
How to Break Out of Frames with JavaScript
In addition, I would take it one step further. Whenever you detect a frame, grab the affiliate ID of the offending site framer, and push that to the server with AJAX along with the URL they are using. Then, either automatically or manually, you can verify that they are framing your site, and cancel their affiliate code one at a time.