A number of persons was denied access to the 2017 edition of the world-famous Tomorrowland festival, based on the results of a preventive screening by the police. The Privacy Commission intervened (NL/FR) in the procedures for summary judgement initiated by three data subjects, who all saw the decision to deny their access to the festival grounds overruled. Further investigation by Committee P (the regulator for the Belgian police) uncovered a multitude of flaws in the screening procedure used, leading to erroneous assessments and thus unjustified refusals of access (twenty-eight out of thirty-three). This raised serious questions on both the screening process and the personal data used. Clearly, it also called into question the practice of preventive policing, also criticized by the Privacy Commission in its recent report on Big Data (NL/FR). Promises were made that this would not happen again. Next year’s wrap-up will tell if the parties involved made good on their promise.