I’ve just received a reply from Gmail when I asked if Bidvertiser and Adsense ads can be placed on the same page. The reply was:

Hi Stephen,

Thanks for your email. According to our program policies, Bidvertiser ads may be displayed on the same page as Google ads on your site.

In general, AdSense program policy does not permit Google ads to be published on the same page as other contextually-targeted ads. You can review this, and all Google AdSense program policies, at https://www.google.com/adsense/policies .

Sincerely,

BIll
The Google AdSense Team

Bidvertiser allows you to control what ads appear on your site so it doesn’t count as contextual. People bid for ad placement. The concern about having both services on a page arose from the fact that bidvertiser ads are almost a complete copy of those that Adsense serves.