If you ask the AdSense team questions about what is allowed by the TOS and what is not, and actually believe that they are giving you correct answers, you should wake up immediately! Their support team is incompetent and can give you contradicting instructions or actuall lead you to breaking the TOS! Here's my story. I emailed AdSense team the same question twice: whether I am allowed to put AdSense ads on "404 Not Found" pages. And I got two contradicting answers: one allowing me to do it and one disallowing. From my understanding of the TOS, the second one was correct, but what if I followed the first one? It would probably put me in violation of the TOS. This means that I could be banned from AdSense by following the advice of their support team! Please read the full story here (including full quotations of emails I got from AdSense): http://digg.com/tech_news/How_Google_support_team_instructed_me_to_break_their_TOS Please be so kind and digg them if you find it interesting!
and for such occasions i keep folders in my mail client (evolution) and store all replies from really important senders such as google or yahoo there with full headers in the original email, you later may prove their own wrong earlier information