User asks question, gets answer. Then it is clarified in the comments by the OP that the question was missing essential details and his real question is in fact not answered.
Should you as the OP or as a third person edit the question to coincide with OP's original intent? In this case the answer will be out of sync with the question through no fault of the answering user. (And the answer will probably be downvoted.)
Should you as a third person allow the OP to edit his question? (With a high enough reputation I think you can roll it back whenever you want to.) To put it another way: the OP is free to post a new question. Should he be forced to do so if he wants a new answer?
The guidelines probably have to take the quality of the questions into consideration, i.e. consider whether the erroneous question is as interesting as the intended one.
Motivation for this meta post:
The question Does unit elasticity has to be at exactly the middle of the demand curve?
An edit was made and rolled back by the same user. I am guessing the reason for the rollback was to protect my answer from being out of sync with the question.
About 6 months ago there was another question, unfortunately I do not recall the title, where the OP made two edits, each of which significantly altered the question. (I answered his original question and his first edit before deciding I was not willing to do endless rewrites.)