That's the kind of thinking that gets people bitten. The only time I hear them rattle is when I've stepped on one already or somebody else has gotten too close. I could tell you stories all day about stepping over them, almost stepping on them, without ever getting any kind of warningAt least the “good” thing about rattlers is they have always given me really good warnings.
I’ve never gotten within striking distance (that I know of) without hearing the signature “get the hell away from me or I will ruin your week” sound.
Unlike scorpions and a lot of other dangerous critters mentioned here.