What is the test for police to stop and videotape motorcyclists for traffic safety reasons?

40. In Brown v. Durham, the police stopped numerous motor cycle club members on their way to a large weekend party at a lakefront property owned by the club. The police videotaped those stopped, and these videotapes were used principally to assist the police in identifying persons who were associating with members of various gangs. The club members sued the police, alleging violations of their s. 9 Charter rights. The trial judge held that “highway safety concerns” were only one of the purposes motivating the stops and one of the other purposes was to gather intelligence about suspected gang members. The trial judge stated that he could not rank these purposes as relatively more or less important to one another.