The courts seem to disagree with you on this point as it pertains to national security letters. I haven't read any of the legal decisions; they're long, and I'

The courts seem to disagree with you on this point as it pertains to national security letters. I haven't read any of the legal decisions; they're long, and I'm not a lawyer, but I see a big hole in the argument you're making. In every non-pathological case I can think of, a person receiving confidential information that they'll be prohibited from disclosing agrees to the confidentiality first. You can't send me an unsolicited letter containing information you want kept confidential and sue or jail me if I disclose that information, but the FBI can (pending the outcome of their appeal of the ruling that says they can't).