in reply to
Should I register a namespace in PAUSE before every cpan module upload?
You don't need to register a namespace before uploading a new module.
As far as I can tell, the only purpose of registering a namespace is to prevent others from uploading modules into subnamespaces (for example PDL::SomeMatrixFunc::ReallyFast). I think it doesn't even prevent uploading, search.cpan.org just shows the "not an official upload" warning in red letters.
I have uploaded about 9 distributions to CPAN, and haven't registered a single namespace for any of them.