Set free in your backyard?
You do realize that if this were to be done cornsnakes would start to become a problem and it could very well cause problems for snake keepers. We're already under scrutiny, people just releasing their snakes to the wild and creating an over population or something is NOT the way to go.
I don't really think a small kink should matter much (this is not the thread to debate that in), however what about a severe kink? What if the snake is obviously refusing to feed and is close to death? Is starving or dying of a severe kink better than putting it down? I think not.
If an animal is suffering "setting them free in your backyard" is not going to ease that. Euthanization isn't something we enjoy, but it IS a necessity. An old dog or cat that no longer has control of their bowels, doesn't have any teeth, and is suffering from joint pain, diabeties, etc would be better off being euthanized. Don't you think?