Chris wrote about Suggestions for Improving Google Quality Score linking to a bunch of threads, but I thought I share a single post from a new WebmasterWorld thread that perhaps can help many of you. I understand how serious this issue is, and that is why you are seeing much coverage on it from here.
Getting the AdWords spider to come back? 1. Copy the site on a different domain 2. Block spiders (web search spiders) from accessing this page (no duplicate content issues this way) 3. Copy your AdWords campaign, but switch the domain name to this new one, make some tweaks so it is not exactly identical.
This may help you and it can't hurt to try.
Forum discussion at WebmasterWorld.