I just read this answer in a blog today (Problogger?). Anyway, the answer is no. Google is smart enough to figure out when it's a spider versus a real browser.
User-Agent: * Disallow: / Noindex: / Code (markup): is not a valid robots.txt file. Do not use this, if you want to stay in the SERP's! AdSense is JavaScript driven => if there is no JavaScript, there is no AdSense page impression spiders do not run JavaScript => spiders do not affect AdSense page impressions Jean-Luc