"Teenaged" audio test?

Here's an interesting item that's making the rounds on the Internet:

A company called Train Horns has developed a way of keeping teenagers from loitering around malls and shops by literally annoying them until they walk away. How?

By playing a constant buzzing sound at a frequency that can supposedly only be heard by people 25 and younger. I'm 23, so I took the "teenaged audio test." I could definitely hear the sound, and it is definitely annoying; but then, I'm not the loitering type anyway.

I'm curious to see if it really is only audible to young people, though. I suspect that anybody with relatively normal hearing levels can hear at this pitch. If you're willing to take the risk, listen to an audio clip here.