My favourite thing about SF is the 'professional' requirement. I think it's unique in that respect, in that I can't think of another technical Q&A site that has both critical mass and such a strict rule as to the types of questions that can be asked.
It seems to me that we should demand the same behaviour of ourselves when answering questions as when asking them; in other words, we should treat professionals in a professional manner. Without pointing the finger, I've seen too many instances (mainly in comments to questions) where the questioner is berated in rude and disrespectful terms, where all they've done is missed out a bit of information, very possibly by accident. Questioners shouldn't need a thick skin to participate here.
My question is: should SF go further than the 'be nice' requirement and, if so, what should the rule look like? I would argue that the answer is 'yes'. SF is different from other SO sites in requiring its questioners to be practitioners. In my opinion SF's community standards should reflect this.