I live in east tn where the mountains are. A lot of bear and hog hound guys here. They hunted "hawgs" year round. They also raise wild ones and release them year round. Its always been illegal, but so is selling bear gaulbladders. It's a lifestyle to them and it's a bigger problem than most think.
With the hog shows on tv, now everyone wants to hunt them, and if they don't have any they want to stock them.
I don't think they are as big of a problem as tv let's on, but in some areas I have seen, like Savanah Wildlife refuge in ga., they have taken over even with hunting allowed there.
Just look at the interest on this site, everyone wants to hunt hogs. I like to hunt hogs too, I just don't want them on my land here. They are just to destructive to native wildlife. Quail and grouse have a hard enough time as it is.