This came up on another list I'm on. It could cause significant problems for those who have difficulty filtering out such noises, such as Autistic people. I suppose it would be ok if it were wired as an on-demand system they could turn on when there's loiterers, but not as an always-on system.
What happens when they disperse from in front of the shop to in front of my house?
That was the deal in my neighborhood a few years ago...the cops quit telling these punks to beat it because at least they were in a well-lit area where they could be kept track of instead of in the dark alleys and streets.
Groups of kids have come and gone over several years that hang out by my townhome. Depending on how they look and act toward me I do different things - last year every time I saw them I'd go out and start talking with them in a really friendly way. I'd talk their ears off about the lamest things! After just a few times I never saw them again, but these weren't punk kids, they were good kids trying to be punks.
Its interesting that many kids aspire to the gangster image.
Classical music may work but it would make me leave aswell.
Where I live right now we just have zero tolerance approach (it sounds harsh) but it works. You get a few kids hanging around near Service Stations and Takeaway joints (Sugar/Fat hot spots) but they generally behave. The locals where I live would not wait for the police to sort them out.