Purpose – The purpose of this paper was to address one of Spotswood et al.’s (2012) “uncomfortable questions”. The paper applies negative option marketing, the use of defaults as a behavioral engineering tool to shape choice, to social marketing and then uses the Hunt-Vitell (1986, 1993, 2006) Theory of Marketing Ethics to evaluate it against President Kennedy’s (1962) Consumer Bill of Rights and the American Marketing Association’s (2014) statement of marketing ethics. Design/methodology/approach – A conceptual assessment of the ethics of negative option social marketing (NOSM) using the Hunt-Vitell (1986, 1993, 2006) Theory of Marketing Ethics as the evaluative framework. Findings – When assessed using the Hunt-Vitell (1986, 1993, 2006) Theory of Marketing Ethics, NOSM possesses neither ethically sound means nor socially desirable ends. Originality/value – This paper contributes to the emerging debate on the use of nudges in a social marketing context and is a partial response to Spotswood et al. (2012).