In the best cases, these agents get redirected to a static copy of the product catalog, or the site generates pages without prices. (The idea is to be searchable by the big search engines but not reveal pricing. That way, you can personalize the prices, run trial offers, partition the country or the audience to conduct market tests, and so on.) In the worst case, the site sends the agent into a dead end.
I think GoogleBot against this cloaking practice. "Cloaking refers to the practice of presenting different content or URLs to human users and search engines" - https://support.google.com/webmasters/answer/66355
Share this highlighthttp://www.safaribooksonline.com/a/release-it-2nd/15134990/