Can I disassociate my udid from a dev account?

A friend of mine who works as an independent developer for iOS devices recently registered my udid with his account, so that I could test his new apps on the latest beta firmware for iPod touch 3G. To my knowledge, this was perfectly legit, as my device was being used soley for development purposes. After a day or so I reverted my firmware back to the current version, and reloaded all my music etc back on. I believe now that he has been selling udid registrations over the Internet, which is something I know apple is (rightly) cracking down on. Nevertheless, I concerned that my device could be linked to his wrongdoing, and that apple may lock it. I have raised my concerns with him about this, but he does not seem to think there is a risk, and is in no hurry to remove my udid from his account. Is there anyway that I could get my udid removed from all dev accounts?

Thanks

Shmiff