Do Dogs/Cats eat Dogs and Cats when they eat their pet food?

I've recently learned of a scandal, rising from this whole contamiated food thing, that road kill, diseased live stock and euthanized companion animals (cats, dogs) are used in everyday Pet foods for dogs and cats to be eaten as a "balanced and nutritious meal." I don't doubt this is true, (I've seen some nasty video footage of this, heres edited content if you'd like to see it: http://K9RX.com has the video, click on the pet food bag, and the lady talking in it has a little more info, on her books website: http://www.critterchat.net/foodpets.htm ) but is there any proof out there that proves this wrong, does someone know something that might save the pet food industry and our pets from the diseases in the tissuses of these rendered animals that they're eating? Or can the pet food companies only denie it? I provide my cats with cats and dogs, roadkill and rotting livestock under the pretense of "Meat Bi-product" check your labels before you feed your best friend his dead brother!