[Zope] UserDB: docLogout, LoginRequired traceback.

Ok, since DC don't support UserDB, this is addressed at everyone else: Can someone tell me what the docLogout page does? How does it get called? I'd like to have the ability to flush the cookie from the users system (useful for when they're on a shared system)... Also, when using cookie-based auth, the docLogin page gets a LoginRequired exception traceback scribbled below it - is there any way to fix/stop this? Thanks, Anthony