CBS Philly reports on how city parks officials are using technology to ward off loitering teens:
When city-run playgrounds and recreation centers want to put up the ‘keep out’ sign during the off-hours, they are turning to an electronic device known as ‘The Mosquito’ to shoo potential young vandals away.
The president of Moving Sound Technologies, Michael Gibson says each small speaker emits a high-frequency tone, said to be harmless, but highly irritating to teenagers and young adults. “They find it extremely annoying and will leave an area within a couple of minutes.”
Councilman Brian O’Neill says, “That happens to be the age group that we want to keep out of our playgrounds when they’re closed at night, when a lot of vandalism happens and destructive behavior goes on.”
When you get older, apparently, your ability to hear the noise goes away. In any case, we've come up with a cheaper way of annoying teens and keeping them out of the park: