Somehow I think if Costner went out there without permission from the feds and/or Coast Guard there would be legal ramifications for Costner.
How so? If he's chartered a vessel to troll around in international waters away for the immediate area of the well head? Freedom of Navigation, right?
You're just out there like anybody else. The fact that your 'centrifuge' is running is nobody's business. And if they did stop him the ensuing public relations disaster would cut against the US Gov't -- not Kevin Costner.
Maybe you are suggesting that Obama's goons would try some backdoor way of punishing Kevin Costner? THAT I could believe.