i'll give people one free pass on creating a new account and then submitting their own stuff. but after that, i expect participation and/or non-self-serving submissions. multiple submissions without contribution is where i start to criticize.
But those people are "giving" with their vote and the people who don't register are "taking" albeit taking something pg is clearly willing to give (bandwidth). So when all you have to do to give back to the community is create a password and click the mouse on a few arrows why wouldn't you.