Rule of consent is a broad term that may apply in many contexts. It generally means that in the given situation, consent must be obtained. For example, in a medical setting the rule is that a patient's consent to treatment must be obtained.
The following is an example of the term used in reference to privacy of records:
FERPA permits school officials to disclose, without consent, education records, or personally identifiable information from education records, to appropriate parties in connection with an emergency, if knowledge of that information is necessary to protect the health or safety of the students or other individuals. See 34 C.F.R. §§ 99.31(a)(10) and 99.36. This exception to FERPA’s general rule of consent is limited to the period of the emergency and generally does not allow for a blanket release of personally identifiable information from a student’s education records. Typically, law enforcement officials, public health officials, and trained medical personnel are the types of parties to whom information may be disclosed under this exception to FERPA.