I was just reading a newspaper article about an anti-loitering device, developed by a Welshman named Howard Stapleton.  Read about it here.

What this machine (named the "mosquito") does -when placed in front of businesses- is emit a high-pitched sound which is apparently audible (and very irritating) only to people under thirty years-old.  (Actually, most people lose the ability to hear this sound once they're in their twenties.)

The aim of this machine is to discourage teenagers from hanging around in and around certain businesses, intimidating potential customers, and causing trouble.  Quoting the article from The New York Times, "Last month, Stapleton (the inventor) gave Gough (a shop owner) a Mosquito for a free trial.  The results were almost instantaneous.  It was as if someone had used an anti-teenager spray around the entrance."

This is interesting.  Dispelling loiterers is really good for businesses.  (I think that getting rid of fund-raisers would be good for business too, but that's a blog for another day.)  I'd imagine that lots of businesses have suffered due to lingering hooligans.

Of course, this device would stir up a swarm of ethical issues.  Why are young people singled out?  Would there have to be a posted warning about such devices being used?  If there is a warning, how long would it take before the devices become vandalized beyond use?  Is the Mosquito safe for people wearing hearing aids?

My answer to this is -of course- "Let the businesses do what they want to clear out their doorway"; but the aforementioned  questions still would need to be resolved.