Five years ago, I was on a hunt in a high-fence ranch in northern South Africa when a friend shot and wounded an eland. He, I, the PH and two trackers followed the animal for four days, dawn to dusk, when the blood trail finally dried up and we could see that he was eating and drinking and not hit seriously.
The point is that we were hunting inside a high fence and we never caught up. Hunting in the RSA is now a big business, and game animals are becoming extremely valuable, so a high fence makes sense because it keeps them from wandering off, and it keeps non-paying personnel from wandering in and poaching your critters.
The plain fact is, that if you have enough acreage inside the fence and enough cover, the game has all the chance it needs to stay alive. Aesthetically it is not nearly so pleasing as hunting without fences, but that is the way things are today.