This is what happened on Saturday night. The Rutherford Rd party was openly advertised on Facebook. According to some posts it had an entry fee which covered the cost of a DJ, security and "clean-up".
It attracted up to 1500 young people, who spilled on to the streets and left a trail of empty cans behind them. Police also found out about the party on Facebook and kept an eye on it until numbers swelled in the evening.
They called it a "Facebook fiasco". The only "security" seemed to be friends of the organisers.
Witnesses saw people fighting and hurling bottles.
Police arrested 15 people, mostly for disorderly behaviour, as they tried to disperse the crowd. Neighbours were left to clean up the mess on the street the morning after.
And now a charity seems to have fallen victim to this loutish behaviour. Students Against Dangerous Driving chief executive Anna Braidwood woke to find her car roof caved in and windscreen smashed on Easter Sunday. There is no law against having a party. Police cannot ban certain people from hosting them. However, they will monitor any future events to prevent this happening again. If hosts don't want the boys in blue on their guest list then keep it off Facebook, plan what to do about gatecrashers and arrange parental supervision. Because a good night doesn't end in the cells.