An important educational subject for engineering students is engineering ethics. Common instructional objectives are to develop knowledge of ethical principles, e.g. professional codes, and to apply these principles to specific situations. Case studies are useful instructional examples and exercises and cases are central to student ethics competitions. Historical case studies emphasize the relevance of ethics in engineering work. Hypothetical case studies can address specific ethical principles and provide great design flexibility. This paper discusses hypothetical cases in engineering ethics in the context of instructional exercises or student competitions. Recommendations are given for the development of versatile cases and for approaching a case study or analysis. Three custom cases that were used in the IEEE Student Ethics Competition are presented as examples.