>Implying that nobody else is capable of editing posts
I actually like this idea, and it has been suggested before I believe. Pokemaster did mention that there would be a way to lock questions.
I'd suggest making it where a question is locked after awarding best answer. If it is answered incorrectly or something like that, then Moderators are able to simply remove the BA and fix things accordingly, not to mention the fact that posts could still be flagged and eventually removed, making the question fair game for being answered again.