I reckon, if the states close their borders for stony corals, the prices will come down all over. The american market is the biggest market in the world.
Considering, the demand for ocellaris worldwide is roughly 50.000 fish per month, the US market takes 30.000 per month.
The coral collectors will collect the same amount of corals, but the demand is not even half. So the prices have to come down.
In my opinion, it does not make sense to ban them, because there will be no environmental impact, except along the american coastline.
It would be more important to convice the people in coutries where the corals get collected, to do more or only coral farming in the ocean. Easy to do and much easier to collect. Growing frags on a tray or diving down and breaking the reefs, that´s a big difference.