There are a couple of us in our dojo that are non-degree seeking students (for lack of a better term) who choose just to train and not focus on achieving rank. It would be kinda nice to have a second term since we literally are "mudansha" by choice to differentiate those who seek rank from those who (for whatever reason) do not. But then as Ron said, semantics don't really count for much on the mats. =)
I've had similar conversations with someone else. It confuses me. If people choose not to "focus on acheiving rank" then they are making usually a pretty strong statement on rank being unimportant to them (as in many orgs you will be graded eventually unless you actively avoid). that being the case, how does it bother the self same people that they are confused with other unranked students?