Suppose you have a $100M batch of medicine but an inside saboteur has put poison in a few bottles and you can't determine which ones. How much is your inventory worth? $0 - or less since you have to dispose if it too. This is because the value depended on the provenance - having a reasonable basis to believe it's what it appears to be.
For a lower stakes example, why is the organic produce in the grocery store more expensive? If you took the labels off and mixed it all together with the rest, it wouldn't be. The value at sale time is derived from a meticulous record keeping process that makes faking provenance comparable in cost to just doing it right.