Risk assessment has assumed increasing salience in mental health care in a number of countries. The frequency of serious violent incidents perpetrated by people with a mental illness is an insufficient explanation. Understandings of mental illness and of the role of those charged with their care (or control) play a key role. “Moral outrage”, associated with an implied culpability when certain types of tragedy occur, is very significant. This leads to tensions concerning the role of post-incident inquiries, and contributes to a flawed conception of what such inquiries can offer. At the same time, understanding of probability and prediction is generally very poor, among both professionals and the public. Unrealistic expectations for risk assessment and management in general psychiatric practice carry a variety of significant costs, taking a number forms, to those with a mental illness, to mental health professionals and to services. Especially important are changes in professional practice and accountabilities that are significantly divorced from traditional practice, implications for trust in patient–clinician relationships and the organisations in which mental health professionals work, and practices that often breach the ethical principle of justice (or fairness) and heighten discrimination against people with mental illness. Copyright © 2013 John Wiley & Sons, Ltd.