Mosquito Silent Alarm Ethnic Issues?

There is a new alarm called the "Mosquito" alarm system, that constantly blairs an extreamly high-pitched squeal. So high pitched, in fact, that you have to be a teen-ager to hear it. As the human ear ages, certian cells in it die. Hearing deterioates over age, we all know that. But a group of scientists recently discovered the frequency of 15Khz, a sound only audible to persons under the age of 30, or occationaly 18. This sound cannot be heard by adults, but causes great irritation and sometimes pain among those who can hear it, namely teenagers. Using this new frequncy, alarms were built and instaled in various shops and stores over England, repelling teenagers "guilty" of loitering.

So my question is this: is it ethic to be treating todays teenagers the same way we treat dogs with a dog whistle? To blare constantly a head-splitting noise that can only affect a certian group, while adults are so oblivious to the noise? Or is it better to prevent "loitering?" What do you think?