Considering mount points, reparse points, and things like subst, I doubt you can ever really know that. Granted, the deviations from the normal scheme are your

Considering mount points, reparse points, and things like subst, I doubt you can ever really know that. Granted, the deviations from the normal scheme are your own making as a user, but so are the places where you mount volumes from different physical drives in a single root hierarchy.