The short answer:
There's no compelling reason to think so.
In the past few months, I’ve received the following e-mail (or some similar version) several times. Generally, the scene is set in Texas (Coleman), but recently the location was switched to Georgia (Ohoopee River, Vidalia, or Lyons).
I had lunch with a friend today and he offered a theory about the fact that these bugs aren't rattling anymore. He raised pigs for years and reported that when he would hear a rattlesnake buzzing in the sow pen, the sows would bee line to it and fight over the snake. For the uninformed, pigs love to eat rattlesnakes. Therefore, the theory is they are ceasing to rattle to avoid detection, since there are plenty of pigs roaming the countryside. “
Means, D., & Travis, J. (2007). Declines in Ravine-inhabiting Dusky Salamanders of the Southeastern US Coastal Plain Southeastern Naturalist, 6 (1), 83-96 DOI: 10.1656/1528-7092(2007)6[83:DIRDSO]2.0.CO;2
Jolley, D., Ditchkoff, S., Sparklin, B., Hanson, L., Mitchell, M., & Grand, J. (2010). Estimate of herpetofauna depredation by a population of wild pigs Journal of Mammalogy, 91 (2), 519-524 DOI: 10.1644/09-MAMM-A-129.1
Place, A., & Abramson, C. (2008). Habituation of the Rattle Response in Western Diamondback Rattlesnakes, Crotalus atrox Copeia, 2008 (4), 835-843 DOI: 10.1643/CE-06-246