On Fri, 10 Jul 2009 07:30:41 +0100, Clint Sharp wrote:

In message , zaax
writes
You could try the 'Mosquito' which is a sound at 17KHZ. It's a high
pitch tone (high frequency tone) that adults can't hear, and kids hate.

Oy, don't you be encouraging that sort of thing, it's not all adults
that can't hear it.

---
zaax
Frustration casues accidents: allow faster traffic to overtake.

I'd also be worried that as these things are inaudible to most adults
(definitely to me), I could have my son in his trolley and he could be
upset by the sound, but I would have no idea why - particularly bad if I
lived in a neighbouring house!

SteveW