On April 25, the one-off Sydney concert of Justin Bieber was cancelled when police decided that the event was too dangerous to go ahead.The concert of the Canadian teen singing sensation was so highly-anticipated that many fans - mainly female teenagers - camped overnight in Circular Quay to get as close to the artist as possible. However, when fans began pushing forward while waiting for Bieber to appear, a crowd barrier was broken and fans near the front of the stage started being crushed. After failing to comply with police directives it was at this point the police decided to call off the event.This incident demonstrates the importance of crowd safety profiling and planning that identifies the background of the artist, his/her lyrics, the demographic of the crowd, suitability of the venue, the weather conditions and the likely behaviour of crowds given other circumstances surrounding an event.Also, the fact that police cancelled the event to minimise the chances of further injury demonstrated the importance of having a flexible crowd management system that allows the capacity to respond to changing or deteriorating crowd safety conditions.