Theoretically, because the activity right now is prohibited to foreign-flag ships under the Coasting Trade Act, a foreign-flag ship could apply for a waiver to carry out the activity, which has happened in the past, so then you will get a domestic ship that will oppose the waiver and say it can carry the empties.
We're aware of a case where that happened. The carrier needed to reposition 400 empties, I think it was, from Montreal to Halifax. The domestic ship owner said it could do that movement and the cost would be $2,000 per container, so that was an $800,000 cost. The cost of transporting those containers on board the ship would have been $2,000 for the domestic ship, and the cost for the foreign-flag ship importing them would have been $300 per container, so it's almost seven times more.
Theoretically, yes, the domestic ship could reposition empties. It will never happen because, even though the foreign-flag carrier's options are not perfect in terms of using rail or importing from overseas, costs will never amount to the $2,000 per container that the domestic ship owner is charging. It exists as an option, but it's one that has never been used, and it won't be used.