Abstract
Preventive detention schemes that aim to protect the community from certain 'dangerous' individuals have long existed. While risk assessment is now pervasive in the management and treatment of many individuals, it raises particular issues when a person's liberty is at stake on the basis of what that person might do. This R.G. Myers Memorial Lecture addresses the ethical issues raised by mental health practitioners providing risk assessments for legislative schemes that involve the deprivation of liberty. It will focus in particular on Australian post-sentence preventive detention schemes for sex offenders that have been held by the United Nations Human Rights Committee to breach fundamental human rights. However, the ethical issues discussed also have repercussions for civil commitment laws that enable the detention of those with severe mental or intellectual impairments.