I've seen them turkey hunting in Texas. Hunted and caught 3 for a Texas rattlesnake roundup. On a Kansas pheasant hunt I walked up on a little one opening day. Mountain biking near Boulder, CO we found one on the trail sunning. Fishing the Miracle Mile in WY a bud and I walking to the river had one rattling at us in the deep grass, but never spotted it. And of course PD hunting in the Pawnee Grasslands, CO years ago. None recently.
The one PD hunting came within 3 feet of us while we were prone shooting. I'm a small guy. At the time 5'8", about 140 lbs (chubbed out to 150 lbs now in my old age). With one hand I grabbed my 10 year old step son and threw him over my head to get him away from the rattler.
All the years I have spent outdoors, those are my only rattlesnake experiences. I've had vastly more water moccasin encounters than rattlesnake growing up in Texas.