In this question I added a segment to the code scope only after describing the essential addition before the answerer in comments and getting his consent to make this addition in a reply comment.

I didn't delete any existing code or changed any existing code and this is something I would generally never do here as I fully understand why it goes against the nature of this site.

I was then, quite rightfully commented by @Mast that I should avoid this kind of editing but it is okay this time as the answerer applied this addition.

This brought me the idea to add to this site a button prevalent only in edit mode like:

The answer's author agreed to this edit in question

The button could be used only if code (scope) was expanded (existing code wasn't deleted or changed). The edit could be saved only after the button was checked.

Opinions?