I vote No, for most of the same reasons already posted by chromatic.
I like Test::NoWarnings. Its author, Fergal Daly, is one of the sharpest people in the Perl QA world. But Test::Warnings is not part of the Perl core distribution. So to earn this proposed Kwalitee metric, I would have to include Test::NoWarnings underneath the
t/ directory in each one of my CPAN distributions. That's pointless.