>>Recently some shops here in the UK where installing high frequency sound devices that teenagers could hear to deter them from loitering outside the shops.
>>
>>http://www.movingsoundtech.com/
>>
>>A classic case of addressing a problem by sending it somewhere else.
>
>We used to sit at the lower frame of a shoe shop, which had a full size glass window, so this lower frame was a concrete outcropping 15cm tall and 15cm out, covered with the same nice green tiles as in the shop itself. We'd be there one hour after school or before - which was the same hour, actually, 13:10 to 13:50, we'd just attend the first or second shift. We were regular there, on days when the weather was nice, for about a year or two.
>
>The staff tried to shoo us away a few times, halfheartedly. I guess they were only worried that someone sitting may bend backwards too far and break the glass. So they called some masons to take off the tiles and cut off half of the width of the outcropping. The shop is still there, still selling shoes (now probably chinese junk), and this lower frame is as ugly as they made it then.
>
>But nobody ever mentioned calling the police or anything.

You often see flats surfaces made impossible to sit on in London. Some spikes or some ridged tiles. Or benches removed altogether in railway stations to prevent loitering or people sleeping on them. Once again a small problem has been resolved by making things uncomfortable for everyone. Bus stops no longer have a nice bench or seat they have an inclined pad for you to lean on. All very well unless your getting a bit older and might like to rest your legs while waiting.