This study reports on qualitative research conducted in the UK with people with Parkinson's Disease and their relatives on the subject of "sham surgery." It explores attitudes toward sham surgery and reasoning about hypothetical participation in a sham-controlled trial. Results showed that attitudes toward sham surgery may not necessarily predict trial participation behavior. A small majority of interviewees deemed sham surgery ethically acceptable with certain provisos, but hypothetical participation was driven primarily by disease severity and a lack of standard treatment options, with a preference for receiving the real surgery over sham. Ethical implications for patient equipoise and the autonomy of patients' research participation decisions are discussed.