We don't get out west enough but we have sen some Rattlers close up.
Good snake boots are breathable and not too hot. I'm not going to walk around the brush in shots and sandals.
Cowboy boots offer some ankle protection but sometimes they strike at keen height and above.
If it is cooler they may not rattle until you are on top, of them or not at all.
Can't count on always being a rattle warning in time.
Never been bit. Closes to being bit was in Tn on a cool morning. Stepped over a rotten log and one was curled up on a large rock sunning himself. He was swimming his head and upper body back and forth. Got away from him and stepped over another one and there was another one in near same position. Picked up a small log/stick to defend myself and there was one under it.I jumped yesjumped back over all three and gave up the idea of fishing.