CPAN -- and probably ppm -- don't add . to the @INC list as including the current working directory in a path used by everybody (which is what @INC will generally be) is usually a Bad Idea™. Were @INC include ., it would be possible for a malign person to include a fake module with a name like 'strict' to perform all sorts of unpleasant tasks, up to and including cd /;rm -fr *.
emc
Insisting on perfect safety is for people who don't have the balls to live in the real world.
—Mary Shafer, NASA Dryden Flight Research Center
