Sometimes users with high reputation end up editing someone else's answer thinking that they are editing their own. This has happened to me several times - both when I edited someone's response and when my answers have been edited inadvertently.
Do you think it would be a good idea to add a visual confirmation of editing someone else's content, say, adding a light background to the editor and/or a message above the editor stating something like "Editing an answer by so and so"?