I don't think it's quite right to think of them as unexpended ordnance. They're more like signposted mines. In some ways they're only useful if they cover all p

I don't think it's quite right to think of them as unexpended ordnance. They're more like signposted mines. In some ways they're only useful if they cover all possible paths through a solution space, since people can just avoid the minefield. How much overhead is there in trying to cover all the paths? Even if you're just trying to catch out the unwary (or explicitly ignorant) who don't look for the mines, coverage of most routes is still pretty important. This joint nature may affect value non-linearly, where A or B on their own are only worth X, but A and B together are worth 100X, or more.