Risk Assessment is a well known and powerful method for discovering and mitigating risks, and hence improving safety. Ethical Risk Assessment uses the same approach, but extends the scope of risk to cover ethical risks in addition to safety risks. In this paper we outline Ethical Risk Assessment (ERA), and set ERA within the broader framework of Responsible Robotics. We then illustrate ERA, first with a hypothetical smart robot teddy bear (RoboTed), and later with an actual smart robot toy (Purrble). Through these two case studies this paper demonstrates the value of ERA and how consideration of ethical risks can prompt design changes, resulting in more ethical and sustainable robots.