Unobtrusive studies raise serious ethical problems. Some research cannot proceed if the observed know of the study and have to give informed consent. In planning unobtrusive studies, the researcher and the human subject protection committee that reviews the plan must assess the subjects’ risks and the researchers’ ability to protect their confidentiality.

Sometimes field researchers have to go to court to protect their field notes. Even if not grand jury demands confidential data, disguised field observations can raise ethical concerns. Such methods deceive subjects about their being observed and may expose behaviours of the most private and intimate sort. The most famous example of such research concerned homosexual acts by men living otherwise “straight” lives.