I still say your anology between hunting situations and vehicle situations is flawed. One is an accident, and one has, or should have, a conscious decesion being made! One situation you have, or should have, control over the out come, and the other, you usaually don't have control on the outcome.
As far as the difference between a rat and a duck, one has the "pest/varmint/disease carrying" label and the other doesn't! An animal that does damage, is known to carry disease, and is labeled varmint/pest isn't in the same catagory as other aniamls!