No, the clothing polygons don't have to match the figure (and shouldn't, for the legal reasons that you alluded to originally). In that case, the morphs don't bear any relationship to the original figure's morphs either, except that they approximate the same 3D surface. That's why programs like The Tailor exist, to transfer a 3D surface from one set of polygons to another, different set. Also, the placement of group boundaries can be quite flexible. In some cases (e.g. toes), you don't even need a group in the mesh at all. The joint parameters take care of the bending, and that's all that's needed. The only reason for requiring groups at all is that joint parameters have a limited "range" - i.e. they can only affect a body part and its parents, but no further.