Yougsters Congrigating

I dont have a large garden and my garden wall is only a couple of meters away and sometime youngers will congragate outside my house and sit on the garden wall, actually saying anything will result in abuse, so my suggestion is an additional feature similar to that used outside shops to stop youths hanging around and that is that video doorbell can emmit a high pitched tone that adults (over 20's) can't hear but is really annoying to youngster and the move on, but only activated in Live View and not motion detection, this is possibly not possible for existing models, would be nice, but furure models could incorperate such a feature.