List seems a little eager to find non-existing parameters:
% perl -e 'use Getopt::Lucid ":all";Getopt::Lucid->getopt([List("l")])' -- -l
Use of uninitialized value $value in substitution (s///) at /usr/local/share/perl/5.10.1/Getopt/Lucid.pm line 445.
Use of uninitialized value $arg in substitution (s///) at /usr/local/share/perl/5.10.1/Getopt/Lucid.pm line 401.
Use of uninitialized value $arg in substitution (s///) at /usr/local/share/perl/5.10.1/Getopt/Lucid.pm line 401.