When a person is hospitalized, family members are legally allowed certain rights, especially if the hospitalized individual is unable to make his or her own medical decisions. But how does the hospital know who is family, and who is not?
For example, if Billy Jones were to be hospitalized and unconscious, and I were to want access to his medical records and control over his treatment, I could arrive at the hospital, provide state-issued ID identifying myself as Steve Jones, claim to be his parent, sibling or child, and have almost-legal access to his medical care. How does the hospital confirm that I am (not) indeed related to Billy Jones, and therefore (not) entitled to his medical information?