rrruger...I can't speak for everyone here, but I am armed while outside at home as well as when away. Where I live, rattlesnakes are a real threat to small livestock such as chickens as well as pets. When I see one on or near my property, I exterminate it. You may think that's cold, but that's just what we do and don't give it a second thought.
I doubt I would waste ammo on a rattler who was simply nearby on a trail.