In one of his pieces about design fiction, science-fiction author Bruce Sterling mentioned that they "are fakes of a theatrical sort, but they’re not wicked frauds or hoaxes intended to rob or fool people." For him, the main difference between them lies in the fact that people engage in design fiction deliberately, in order to discover the implications of a certain number of changes in society, through a set of prototypes and props. Such statement implies the existence of a design fiction ethic. Given the focus of the upcoming edition of Primer in Helsinki, our talk will focus on the relationship between design fiction work and trust. More specifically, we want to look at the close connections with hoaxes and fake news in order to highlight differences and common traits. Our aim is to rely on such analysis and a series of projects in order to propose a set of principles and to question what a design fiction ethic would entail.