OK. I understand where you are coming from, but I'd have to disagree from a business perspective. If you're running a Q&A website you don't want users to be able to hide questions after they ask them. These questions have value for both other users and SEO. If people who are simply registered users start hiding questions they previously asked, it can conceivably cause all sorts of problems. Of course, someone can always email in to hide a question, but that's unlikely since all questions are pretty much anonymous.