Stores Experiment With 'Teenage-repellents'

"The device, called the Mosquito...emits a high-frequency pulsing sound that...can be heard by most people younger than 20 and almost no one older than 30. The sound is designed to so irritate young people that after several minutes, they cannot stand it and go away....Some shops [use] 'zit lamps,' which drive teenagers away by casting a blue light onto their spotty skin, accentuating any whiteheads and other blemishes."