In this personal account retracing forty years of ethnographic investigations conducted in the People’s Republic of China, Sabine Trebinjac looks at the circumstances in which she gathered and shared her data, as well as her constant concern to protect her interlocutors. In a changing and unpredictable political context, devising strategies to ensure the present and future safety of ethnographic data is central to anthropological research. The experience of Chinese authorities’ use of data in the past is a powerful reminder of the responsibility of the ethnographer, who is sometimes better informed than their interlocutors, and of the possible dangers of making data available.