Asymmetry in knowledge and power between (1) physicians and patients and (2) physician educators and their students creates a climate for possible abuse in both sets of relationships.
Advance directives do not always resolve questions about the best care for patients who no longer have decision-making capacity; physicians and patient surrogates can take alternative approaches to arrive at the best care decision.
Even if they are not sick, people in quarantine are still patients; the physician is responsible for their well-being and may find that it is necessary to advocate for them.