OT: captchas

I have a question for the CS majors ;) Captchas http://www.captcha.net/ http://en.wikipedia.org/wiki/Captcha Has anyone ever seen any writing on the idea of caching the different captcha images, manually decoding them and storing the "meaning" of the captcha in a database. Then cross referencing the "meaning" of the captcha with the image filename. That way you would have the ability to have a bot load a page/service protected by a captcha, read the image filename, and decode the captcha. Is this a valid idea?