It’s more like, you can fence off your cattle but you can’t fence off the birds and the bees. So even if the cattle stay within their limits, the grass relies

It’s more like, you can fence off your cattle but you can’t fence off the birds and the bees. So even if the cattle stay within their limits, the grass relies on bees coming in from neighbouring farmland to stay healthy. If you pave the area outside a cattle ranch the grass inside will die on the borders. So you have to zone the land outside the fences to make sure it some other ranch or else left wild. The same with spectrum. Adjacent frequency bands have to allocated to uses which do not produce a lot of interference that travels very far or is used very much.