I've never heard of that, but it sounds interesting. I don't know just how much predator pressure your area has, but I would say your best bet is to focus primarily on making the coop predator proof, so you know they are safe, at least during the night. Lights and scaring devices may or may not work initially, or may work only for a while.
I live at the edge of the forest/mountains and everything from bears all the way down to weasels are around at least occasionally. So far my coop has kept my flock safe at night, and I haven't had anything attack during the day while they are out free ranging.
