The Justice Department has proposed a rule change for the FOIA to allow government agencies to deny that records do not exist when they do. As it stands now the government can withhold information and issue a Glomar denial that says they neither confirm nor deny the records exist.
Open government advocates say that the rule change would deliver a blow to transparency in that with the proposed rule, those seeking information would be inclined to forego appealing denial of the request concluding that the information doesn’t exist. -db
From ProPublica, October 24, 2011, by Jennifer LaFleur.