and for those of us who are a little hard of hearing, the rattle doesn't help us much anyway.
I stepped on one a few years ago. Didn't hear a thing until the guy in front of me said something, then I heard it! If your hard of hearing and not listening for that sound you can miss them. The guy behind me told me" "...that snake must have needed glasses cause he missed by an inch!" I danced out of the way then stopped to look at him. He skedattled down a hole.