They must be different where you've been compared to where I've been. In my experience, rattling is the snake's last resort. If you hear a snake rattle, you're already too close to it. Heck, I've had one strike and crawl off without rattling.They're not hard to avoid. Listen for the rattle, watch where you step, and proceed slowly on sun-exposed rocks. I've walked up on maybe 12 of them and none too close for comfort.