But just to play devil's advocate on the aforementioned ones:
Re: the fix: I agree about the pandemonium as it all happened could prevent it. Also it could have been found before, but remember it really only disorients them, doesn't kill them. So maybe people have found it, but it was too late for it to really be a "fix." Also, if you find out they track you by sound really early, do you really want to start making a bunch of different sounds to see if one will hurt them?
And living by a waterfall make sense, but waterfalls generally aren't on the most habitable land. I would probably try to make my way to Niagra, though.