 When emergency intervention is needed but normal consent cannot be obtained, say, because the patient is unconscious and neither she nor her family’s specific preferences can be identified in time, proponents of informed consent often justify intervention by invoking a potentially different form of consent. They say that presumed consent obtains, even if actual and express consent does not. Presumed consent is also often invoked in order to legitimize a general policy of harvesting organs from healthy deceased persons to use in transplantation unless they explicitly indicated their opposition, and a similar general policy of testing all incoming patients for HIV except those who explicitly request not to be tested. Such policies reverse the usual default assumptions about what is permissible and place the onus on any individual who has reservations, to “opt out.” The underlying thought is that when opting out remains easy, so-called presumed consent is perfectly consonant with patient sovereignty (Sunstein and Thaler 2008).