A bad date list (also known as a bad date book or Ugly Mugs) circulates details of persons that may pose a threat to sex workers.
Bad date lists contain reports of 'bad dates' or incidents of violent or dangerous clients or other persons, which describe the incident, and frequently provide a description of the person, their vehicle (if applicable) and their phone number (if applicable).
Bad date lists can be handed out to outdoor sex workers.
Bad date list websites are also frequently used, mainly by indoor sex workers.
The first Canadian bad date book was published in Vancouver, Canada by the "Alliance for Safety of Prostitutes" (ASP) in 1983.