
I've been wondering about this myself.  The house wiring thing is really
hokey.  There is no doubt that high pressure ultrasound is annoying, but to
whom?  Given that these devices have been advertised to be effective against
everything from insects to rodents to nasty dogs, what is to say that my
insect repeller won't just annnoy my dog and give me headaches?  Could there
be that much selectivity in frequencies?  Have there been ANY studies
on the effects of various pressure levels, bands, and sweep patterns on
various life forms?

And how effective could they be?  I certainly would not want to tell anyone
that they are safe from nasty dogs because they were carrying a piezoelectric
buzzer...
