And by not gritting you are ignoring your responsibilities. It doesnt take a brain surgeon to know when the ground is likely to be icey, you cant debate that, whether you are responsible or not.
Your analogy if adopted by guys that dig up the road would discourage them putting bollards, signs and hazard tape round their work area because its then acknowledging that theres a risk.
Why did the guy fall? Did he trip over your signs, slip on the ice, get tangled in your hose?