As I understand it, they wait until they find an infringement THEN they file with the copyright office. Their suits ought to be thrown out of court, or at least limited to cease and desist orders to the infringing parties.
There should be no money judgments ordered for this kind of blood-sucking-attorney shenanigans.
Newspaper Chains New Business Plan: Copyright Suits
http://www.wired.com/threatlevel/2010/07/copyright-trolling-for-dollars/