It's been a while since I've gotten a fully straight answer from google adsense. Google is classically unclear about certain topics. I asked them about putting adsense on a page I'm holding a contest on. Here goes: Q: I plan on starting a payed myspace layout design contest very soon. Is putting adsense on a myspace layout design contest page allowed? A: Hi Juan, Thanks for your email. This appears to comply with our program policies. As you may know, you're welcome to place Google ads or an AdSense for search box on any website that complies with our program policies (http://www.google.com/adsense/policies). There's no need for us to review the site beforehand. However, we do ask that you use your best judgment. While we look forward to helping you monetize your other sites, please don't forget that we do monitor all sites displaying Google ads or an AdSense for search box to ensure compliance with our program policies. If we happen to find that a site is violating our policies, we may contact you and ask that you remove the Google code. Thanks for your cooperation. Sincerely, Sean The Google AdSense Team
Sounds like same old answer they always give. They never tell you yes or no. They always say read terms so they do not have to tell you if it is ok or not. You did get them to say it is ok to have paid contest on site. That is more than the most emails from them.
I'm trying to say contests and adsense is OK. I call that nonambiguous. I've honestly NEVER heard that sentence before. I've always gotten everything except that one sentence.