A consultation is private, so anyone the practice adds to it needs the patient's agreement first. Before a medical student, another observer, a visiting practitioner or an interpreter the practice has arranged joins a consultation, the patient is told who the person is and why they are there and is given a genuine chance to decline; the consent is recorded in the patient's record. Patients may bring their own support person without this process.
The graph holds this control, the 0 it maps to, and the evidence behind each claim, over MCP and REST.