Dangerous bouncer

Some people feel that children should not hang out or play at entrances of certain public areas, stores or other businesses. The noise device, developed in The United Kingdom, was designed to drive them away.
The noises emitted from the device are high frequency sounds at about 18.5 kilohertz. At these frequencies the sound is extremely uncomfortable for most kids and young adults under the age of 25 years. People older than 25 years of age are usually unable to hear such high pitched sounds.
Permanent damage
An investigation by the German Bundesanstalt für Arbeitsschutz (Worker’s Protection Agency) found that the noise devices produce noise levels as high as 104 dB. At such extreme intensity the noise can cause permanent hearing damage.
People exposed for longer periods of time to such noise levels may suffer from dizzyness, lack of balance and headaches.
Infants at greatest risk
Children and young adults move away from areas with such noise, but infants and newborns, who may be seated in strollers, can not. Their parents are unable to hear the noise and are unaware that their children’s hearing is threatened. The results can be serious permanent hearing loss or other hearing damage for these vulnerable children.
Source: Forum gutes Hören, March 2008