In Tennessee, all snakes are protected by law from being killed. Even the poisonous kind. (Rattlers, Cottonmouths and Copperheads. We’ve had several people die from Copperheads in the past year, as it happens–and they aren’t even usually fatal! Some snakes, typically the ones that kill by biting like the otherwise rather harmless garter snake, are just as poisonous as rattlers but lack an efficient delivery system and pouches for storing it.)
Several years ago, a highway patrolman caught a woman backing up to see if she had run over a rattler, a couple of counties over from here, and fined her stiffly for it. Insanity.
But the point of course is to protect the relatively harmless constrictor (and biting) snakes from being killed along with the poisonous ones, since all of them help keep the rodent population in control, thus also reducing grain lost to rodents.
Still, they can dang well fine me: if I find a poisonous snake I’m killing it. (My area of Gibson County tends to run heavy with cottonmouths, even though I’ve never personally seen one alive in the wild somehow. I’ve seen copperheads before on rare occasion. No rattlers around here, for some weird reason. Not that I’m complaining.)