In developing the SSO plugin for PluggableAuth, I ran into a problem when Microsoft's crawler was hitting the wiki. The crawler presented SSO credentials that were authenticated by the SSO plugin, but then PluggableAuth would send a redirect which and (combined with another bug that resulted in a redirect), this meant that the crawler thought it was in a redirect loop.

I avoided the problem by adding a hook that would allow me to bypass the redirect if a user in the bot group was the user authenticated.