look in the "Predators and Pests" section of the forum, there have been a number of threads on the subject.
I would be =astonished= if it really worked (for one thing, this nonsense about predators' eyes flashing red -- they only do that *when you shine a flashlight etc at them*, so unless a coyote is going around with a penlight he would virtually never *see* red flash from anything's eyes!). I have not actually tried it.
I would so, SO not count on relying on it for anything; but if you wish to stimulate the economy and use it as an auxiliary to an already-good system of predator defenses, sure.
JMHO, good luck, have fun,
Pat