procedures that require that no contents of any communication to which a United States person is a party shall be disclosed, disseminated, or used for any purpose or retained for longer than 72 hours unless a court order under section 1805 of this title is obtained or unless the Attorney General determines that the information indicates a threat of death or serious bodily harm to any person..
In other words, for all the arguments in the world to unmask the identities of US citizens incidental to surveillance of a foreign person or entity, you cannot retain, disclose or disseminate this information without a FISA warrant.
What is the penalty for breaking that part of the law?