What I think should be the policy, as people have expressed here, is personal preference, if you think a question sounds fishy, don't answer it, no one is forcing you too, no one says you must answer questions asking for passwords, if you aren't clear on whether you should or should not, don't, and someone who is decided they will/want to answer it will answer the question.
I personally don't feel bad in the slightest giving someone the easily obtained information on how to get around a mac password (and I usually give 2 or 3 out of 300 ways).
I'm sure we also all remember the "while on vacation in Nigeria..." question.
