re: Deer deterrent whistle for vehicle, is this snake oil?

As a teenager I grew up in a rural area and hit about 4 deer in my car but narrowly missed probably 30. My dad put these on my car and I never hit a deer again. Could just be luck, I don't know. What I noticed after they were installed is that rather than running away a lot of the deer would just stand there and freeze, looking confused as I drove by.