As far as I'm aware, you can't edit any form of question i.e. some sections are for questions, others for cool things, code repositories, discussion etc. So my understanding is that "questions" are not editable.

If memory serves vroom told me once that this is nothing to do with possibly imflamatory material being added to a post after moderation. It was to stop people changing the question, thus making the following discussion wrong or irrelevant.

I think a post whose only purpose is to clarify something that's not editable is a kludge at best. I fail to see how not being able to modify the original question, but being able to modify replies adds any benefit.

Regards.

Nuance