I think scain is right. However, it is too late to do a site-wide policy IMO, because it would be retroactive (i.e. would cover previously posted code without the authors' permission). So the best we can hope for is that monks optionally define the license with code posts or add something like this to their homenode:

Unless otherwise noted, all code authored by "$code or die" on perlmonks.org is free software which you can redistribute and/or modify under the same terms as Perl itself.

Which /me is about to add to my homenode. You should be able to negate this license on individual code posts.

Updates: removed superfluous "it" from license statement - btw what's the correct spelling of license?
Added link to perl license.

Simon Flack ($code or die)
$,=reverse'"ro_';s,$,\$,;s,$,lc ref sub{},e;$,
=~y'_"' ';eval"die";print $_,lc substr$@,0,3;