Now come on, this must be a joke, surely? A high-frequency sound, audible only to teenagers, which keeps them away? It's an attractive idea...

Presumably it's audible to anybody younger than that as well, so if you're wondering why your baby is crying in the supermarket, or why your dog seems particularly restless outside, here's another possible reason!

Anyway, the teenagers are apparently getting their own back.

I think they're probably both hoaxes...