My economist friends tell me that relegating the purchase and sale of looted antiquities to the black market would likely increase their price. The competition for looted pieces would be just as intense as long as there were a significant number of buyers. So the price would go up because (1) the costs of making transactions would increase and (2) the product would be rarer. No longer could people see the items in a museum; the only way to enjoy them would be to buy them—on the black market, at prices perhaps even higher because the objects could no longer be viewed elsewhere.