Do you tell the user on signup to print an in-case-of-emergency-break-glass password which is only ever to be used to get into a locked account and other special circumstances?

It may seem over the top but seeing as it's unique across service providers, I think it's a hell of a lot better than the overly abused "what is your mother's maiden name" type questions. I consider these questions to be in the same boat as sharing passwords between websites (since they are)!