My daughter and son in law moved to a house on a corner, it had been empty for a year or so and while it was empty. The local kids (aged from 7 to fourteen) had taken to using the back garden as a 'hang out place', letting themselves in via the gate, They played football, played music and we are sure there was underage drinking and smoking going on to by the older ones. The parents of these kids did nothing to stop them doing this.
Two days after moving in my daughter came home from work to find a dozen kids having a riot of a time in her garden, they'd taken over the lawn, the garden furniture and the shed, she thought the shed was on fire by the amount of smoke coming from it...three of the little 'darlings' were in there puffing away on ciggies. She told them to clear off...nicely...the did eventually after some grumbling "But we always play in here, our parents don't mind, they know where we are".
My daughter thought that was and end to it, but no, they kept coming back, every time they were out at work. My daughter put a padlock on the gate, the kids then began to play football in the street and of course the ball was booted over into the garden, which meant they climbed over the fence. Or they'd boot the ball against the fence deliberately, this went on for weeks until my daughter lost her shit one day and screamed at them, she threatened to call the police and report them for trespass. She also refused to return balls unless their parents called to collect them, this didn't go down too well... One parent knocked, expecting a row but DD was very polite and returned the ball with a smile and he walked off saying 'I thought you said she was scary' to his son, Some of the parents were most put out that their free playground had had time called on it. DD asked if they'd like her and her D,H. to just walk into their houses and plonk themselves down on the sofa to watch Corrie All is quiet now two years later.