The stampedes aren't, but hogs are a horrible invasive pest that causes many billions of dollars of destruction per year. They've tried trapping, poisoning, everything. The only thing that has any effect on the population is some serious firepower. The problem is so bad that you can hire people to fly around at night in helicopters with sniper rifles and thermal vision to shoot hogs. I've helped a few friends with hog control, and you'll often startle 10-20 at a time and then they'll go into hiding and you're done for the day. You need to put a lot of bullets downrange fast to have any effect.