It is a characteristic of ethnographic field research that it seldom evolves according to plan. Once in the field, researchers must adapt their research designs in response to circumstances and people they encounter. This paper exemplifies this by discussing actual research carried out for the project presented in this paper. The project examines social and spatial transformation in Tibetan nomad communities related to motorized mobility and mobile telecommunication. Geographically, research was located in a contested region of Western China and carried out without official permission. The resulting difficulties and challenges were negotiated by doing guerilla-fieldwork, a term introduced to describe fieldwork pursued without state authorization. This article exposes some of the challenges, both practical and methodological, of guerilla-fieldwork and discusses their implications regarding research ethics. It contributes to current discussions on research ethics and argues that guerilla-fieldwork requires a heightened measure of transparency, openness and reflexivity of the researcher to maintain ethical integrity.