A wall-mounted device that emits a high frequency sound audible only by teenagers and young adults is showing up in North American cities, the aim to disperse loiterers. Whether you can hear the noise or not depends on how much your hearing has deteriorated. Civil liberties groups are up in arms over the device for obvious reasons, yet nearly 1000 units have been sold here by "Kids Be Gone". England's government-appointed Children's Commission describes the device as a weapon that infringes on the basic rights of young people but a South Carolina School District says "Now, there's no confrontation at all; they just get aggravated and leave within a few minutes." after having installed the device. I personally don't like the idea of painting all young people with the same brush, it does smack of discrimination in my mind and what are the potential health risks? CNN story here.