['We sought to characterize persons who requested to opt out of an exception from informed consent (EFIC) cardiac arrest trial and their reasons for opting out.', 'At one site of a multi-site, out-of-hospital, cardiac arrest EFIC trial (September 2007 - June 2009), persons who did not want to participate in the study could request an opt-out "NO STUDY" bracelet to prevent trial enrollment. We surveyed all persons who requested a bracelet by phone interview, web or mail. Opt-out bracelets were advertised in all public communication about the study, including community consultation and public disclosure efforts. Survey questions included demographics, Likert scale items about attitudes toward the trial and research in general, plus open-ended questions. We used descriptive statistics for standardized questions and qualitative analysis to identify common themes from open-ended questions.', 'Sixty bracelets were requested by 50 individuals. Surveys were completed by 46 persons (92% response rate). Seventy percent of respondents agreed emergency research is important, but 87% objected to any research without consent. In the qualitative analysis, 5 overlapping themes emerged: questioning the ethics of EFIC research; concerns about how the study would impact end-of-life preferences; subjective emotions including sarcasm, anger, and allusions to past unethical research; negative reference to unrelated public health controversies; and objections to the study protocol based on misinformation.'] Do why persons choose to opt out of an exception from informed consent cardiac arrest trial?