I think the main reason we don't want people reposting their question elsewhere is that it means there's more than one thread with the same question.
As Sue said, the AAQ forum is set up to be user-friendly (particularly for new members) and so if they can't find (or are unaware) of the specific forums for a particular topic, it's easy for them to ask their question here. If appropriate, an admin can move the thread to the more specialised forum. I generally try to allow it to get a couple of replies first and then post that I'm going to move it, so at least the OP gets the email with the link to their thread before it's moved.
