First, no one knows what is in Obamacare so I am not sure we know how he has "changed" that law. Whatever BP decides to voluntarily do that is on them. Obama's appointees can easily decide not to issue any more drilling permits to them in the Gulf. He sort of has them by the balls that way.
I agree to a point. If Obama makes a declaration about NICS checks not getting a pass after 3 days and all the FFL's fall in line, then the letter of the law may not matter. I really find it hard to believe that all the FFL's will go along. I also think if he start denying NICS checks right and left, gun stores will find grounds to sue as he is then directly affecting them. There is no way word won't get out that he is doing it.