On the local TV news yesterday a shop in Leven, Scotland has installed a special alarm. This shop is a magnet for teenage gangs who hang about in packs outside. They have caused problems with graffiti, noise, intimidating and accosting local residents. This alarm emits a high pitched mosquito type whine that seemingly can only be heard by people under 25 years old. The annoying sound is switched on when gangs congregate and disperses the crowd seemingly. I believe that it is used succesfully in USA. More shops are set to follow suit and the police recommend such a system. In my opinion this is not a solution as it only moves the problem on and the kids will soon return.
I am shocked that this problem cannot be resolved in any other way. I cannot see why the youths cannot be arrested and their parents found and punished for failing to control their offspring.
Perhaps an alarm could be invented audible only for the over 25s to get lazy parents off their lazy backsides and see what their kids are up to and keep them under control. That is the root cause of the problem lack of parental control.
Has anybody heard of these alarms and how they work exactly? Is it true that our ears change as we get older and that a sound can be inaudible just to folk over 25. The implications are huge when it comes to music. Can you imagine records with sounds inaudible to grown ups yet clear as a bell to teenagers.

http://www.soundclick.com/bands/songInfo.cfm?bandID=687727&songID=5238055