Conflict follows device that drives away teen loiterers

Devices called the Mosquito have been sold in the US and Canada. These devices are meant to drive loiterers away with the high frequency sound that they make. But, the interesting part is that it can be heard mostly by people in their teens and early 20s, because they are the ones who still have sensitive hair cells in their inner ears.

http://www.cnn.com/2008/TECH/04/23/teen.be.gone.ap/index.html