Mosquito Tones

I've finally gotten around to checking out the so-called "Mosquito Tone" that I've been hearing about for awhile. For those who aren't familiar with it, a mosquito tone is a 17 kHz tone that can be heard by younger people, but not usually by those of us over thirty. Some kids are using it as a ringtone so teachers or parents won't know when they get calls or text messages. Ironically, it started as a system to stop kids from loitering.
Plasticmind//Journal has a series of tones to determine what frequencies you can hear.
As a music fan (and as someone approaching middle age), I don't like the thought of losing my hearing, so I was hoping that it was an urban legend or at least that I'd be able to hear it. Alas, I couldn't hear the 16, 17 or 18 kHz tones. My 5-year old boy could, however (I even tried to trick him, but he always got it right).
I don't think I'm missing much though, considering how my ears felt after listening to the tones. It was designed to annoy people, after all.
Here's a more thorough article with an explanation of Presbycusis - the gradual hearing loss associated with aging.