BACKGROUND Legal and ethical obligations do not always align when doctors become aware of a clinical situation involving a person with whom they have no pre existing therapeutic relationship. Noting a potentially malignant skin lesion, such as a melanoma on a person outside the clinical setting, provides a pertinent example. OBJECTIVE The aim of this article is to describe the legal, ethical and professional considerations surrounding proffering a dermatological opinion in the case of suspected melanoma outside the clinical setting. CONCLUSIONS The application of professional and ethical standards may require the doctor to act in some way to alert the person of their findings in a context whereby there is no defined positive duty to do so in Australian law. The degree to which the doctor is ethically obligated to provide an unsolicited dermatological opinion is affected by numerous and, oftentimes, competing factors.