The best prevention for deer-auto collisions isn't those whistles on my bumper - though I've seen them work in one of those near-misses of mine. The best prevention for deer-auto collisions is a .308 bullet, and HSUS will change its tune fast when one of its leaders is killed by a deer - like the motorcyclist my mother saw fatally hit in front of her in a deer collision.
No they'll just sue the Fish and Wildlife service like PETA is doing.