Code:
because everything that is _inside_ the MPD is kind of its internal implementation detail.
Two points:
1) The errors you mention are caused by "imported, unofficial files". That parts are unofficial because they are not perfect at the time the model is created. So there will be errors in that model files, as long as unofficial parts are used!
2) Nowadays it is very easy to extract model, submodels from mpd content files (at least with MPDCenter). So each separete file entry is noticed and therefore should have a correct naming to not collidate!