That's one way to look at it. Another is that they need the fees to off-set their year-round efforts at hog "control" (not to metion the liability issues that have unfortunately become the norm these days). Several of the big ranches in TX use helicopters to chase down and shoot as many pigs as they can find...an expensive effort, and still unlikely to make much of a dent.

Here's a hog control option I think most of us can appreciate:

http://www.hdlgirls.com/