Paying out on land speculation?

On NPR this morning I heard a story, NPR : Western Voters Weigh Shift in Property Rights, that sounded to me like voters were about to legislate that the state is liable for any changes that affect the future value of land. That is, if neighbor A lets the land there become a toxic dump, then neighbor B can have the state pay the reduction in *future* land value caused by neighbor A.

Of course, it would have to be an ordinance that allowed A to put a toxic waste dump on the property, but, still. It takes the risk out of speculation. One of the main reasons land speculation tends to have a large payoff is that it is extremely risky. Get rid of the risk, and its easy money. Too easy, basically.