I know this is a railway forum, but in the gents loos of most Transport for London Bus Stations they play classical music, when I asked a friend of mine who was a London Buses area manager, he said that research had been undertaken which discovered that the type of people who are likely to cause mischief leave because they cannot stand that type of music, so the toilets do not get vandalised and have to be closed therefore inconveniencing me, I do however find it quite amusing peeing with Handel's Water Music playing in the background.
TfL have also put blue filters on lights so that drug addicts cannot inject themselves as they cannot find their veins with blue lighting.
On the Tyne & Wear Metro they play classical music at all the stations for the same reasons (or they did when I was last up there).
I support this sort of thing if it means that the undesirable types go elsewhere to make their mischief, rather than vandalising public transport facilities, or making users feel unsafe by hanging around there.
However I do wish the recordings were of a better quality as some of them sound awful.