Allan, at a second thought, you might be correct. I may be committing an epistemological error. But (and this the crucial linchpin in your example) is the government really saying "we are withholding evidence from the citizens?" Can we construe their reluctance to open and reveal everything they know as "hiding evidence"? A second and related question: Are you sure we want the government to reveal everything they know about (say) relations with China, cyber security, or nuclear weapons?