To follow up on what Alinact says, on Tyneside, a problem with youths hanging around on the Metro platforms was cured by playing the "wrong" sort of music over the public adress system. It seems they couldn't bear to lose thieir "street cred" by appearing to be listening to the likes of Bing Crosby and Max Bygraves.
It certainly adds a new slant to "Zero Tolerance"
C-flat.