Did you hear that? If you're older than 24, you probably didn't.
It started out as invention to keep loitering kids away: a noise, at a frequency only teenagers could hear, blasted into the parking lots of convenience stores. Now the high-pitched sound has made it into the world of ringtones. Mosquito Ringtone describes their product as "a tone outside the audible range of hearing for most people over the age of 30." The ringtones are available for free, and the Mosquito website even offers a sampling of frequency sound bites to test your hearing.
The reason for the sneaky sound? So kids can field texts and phone calls undetected by parents and teachers. Hmm ... one more reason to ban cell phones in school?
Should parents be concerned?