tags are for searching; it's not useful to search for maps based on who timed them (in fact it's harmful to search results cuz u'd find mapsets that are almost entirely unrelated to the mapper you are looking for)
agree with pish, giving credit is important but tags isn't the right place.
i rly wish we had some fields on site for stuff like this cuz all of these tagging RC problems are caused by the lack of dedicated fields... grrrrrrrrrrrrrrr