If they only sold barrels from the reserve to companies in the US at artificially low prices compared to the rest of the world, what would stop those companies

If they only sold barrels from the reserve to companies in the US at artificially low prices compared to the rest of the world, what would stop those companies from taking it and selling it for a profit across the border instead of passing the savings down the chain to US consumers? As far as I can tell, this is literally the only way to make such a strategy work.