I was learning about responses to zombie attacks the other day. It was pretty intense. Basically, some statisticians and pathologists who work for the Center of Disease Control have run some simulations about the spread of the "zombie disease" (if one ever stuck). If there is any sort of hesitation on anyone's part in regards to killing any zombie will result in a massive outbreak of the zombie virus and will take over the world. The only way we would be able to control zombies is to immediately remove the zombie head from the zombie body as fast and in any way possible. If there is any sort of conference on ways to "save" them or a humane way to treat zombies, modern civilization as we know it will collapse.
So just remember that. You should probably mentally prepare yourself to attack when you see someone with zombie-like characteristics.