Does AdSense returns adverts to spiders when they visit? e.g, if MSNBot pays a visit, and Adsense realises from the IP & UserAgent info that it's MSNBot, does it bother to go to all the trouble of processing and returning the ads?
True, the bot wouldn't show the display, but would Google return the completed HTML output if a major bot requested the file? Although I suppose MSN & Yahoo would skip over the Google AS include instead of requesting it. I was thinking more about the bandwidth involved for AS and the bots.