After several months, I now turn my attentions to the 'Territiorial Markings' Manifesto node for the first time; investigating public signage, graffiti, desperate pleas and other related imagery. More shortly.
Compound Security Systems of Wales makes the Mosquito teenager-repellent:
"The Mosquito ultrasonic teenage deterrent is the solution to the eternal problem of unwanted gatherings of youths and teenagers in shopping malls and around shops. The presence of these teenagers discourages genuine shoppers and customers’ from coming into your shop, affecting your turnover and profits. Anti social behaviour has become the biggest threat to private property over the last decade and there has been no effective deterrent until now.
With an effective range of between fifteen and twenty meters Compound Security Devices field trials have shown that teenagers are acutely aware of the Mosquito and usually move away from the area within just a couple of minutes. The system is completely harmless even with long term use…
It seems that there is a very real medical phenomenon known as presbycusis or age related hearing loss which, according to The Merck Manual of Diagnosis and Therapy, "begins after the age of 20 but is usually significant only in persons over 65". It first affects the highest frequencies (18 to 20 kHz) notably in those who have turned 20 years of age". It is possible to generate a high frequency sound that is audible only to teenagers."