In looking at the Module code, it seems that there is some confusion
over the nature of the Module hierarchy.  In certain circumstances, it
seems that the hierarchy implies more than just a naming mechanism (i.e.
if you unload a module, it automatically unloads the submodules by
default).

I think I'm of the opinion that the purpose of hierarchy should be
strictly confined to naming.  There should be no other relationship
between modules and submodules implied by the name hierarchy whatsoever.
Names should be resolved by looking within the current module and any
imported (and consequently pre-requisite) modules without regard to the
name hierarchy.  In fact, it would probably not be useful to think in
terms of modules and sub-modules at all.  But rather, they are all just
modules, some of which may have elements of their name in common.

- Stephen