Glenn Reynolds has a great post about when it’s appropriate for the press to claim it doesn’t have to disclose information used in a story. Here’s the money quote:
what’s revealing — and troubling — is that these media organizations think that they’re exempt from the obligations faced by ordinary citizens. And, in fact, I think that rather than the First Amendment, another provision from the U.S. Constitution is relevant here: ‘No Title of Nobility shall be granted by the United States.’
P.S. If you want a better practice, check out this Ultimate Guide.