I've always admired David Vestal's stance on non-disclosure agreements: he doesn't sign them. He won't accept information with any limitations attached. As he puts it, "I'm in the disclosure business."
Unfortunately perhaps, most journalists in any field know things they can't talk about. Either they themselves have promised not to disclose, or the information was passed along privately by a friend or industry insider who was sworn to secrecy and who has asked not to be betrayed.
It's not like these are matters of national security or scientific urgency, and it's not like there are legal consequences. We're playing in a relatively benign sandbox.
However, a betrayal is still a betrayal, and people who betray their sources or their friends lose them. Some things I know I just can't talk about; that's just the way it is.
And now I won't say anything more about that.