“so basically the airlines are stealing when they close down someone’s mileage account.”
That was I believe a portion of the claim in Ginsburg vs Northwest
“except they cant be prosecuted since there was a deregulation.”
You misunderstood a portion of the claim made by the airlines. They argue that due to deregulation there are no applicable laws (since they argue this is related to the fare)that they violated and therefore the case doesnt belong in court. the airlines won this argument at the first level, a state court of appeals overturned the lower court and the case made its way to the supreme court.
“but good faith laws really allow you to sell miles.”
Part of the Ginsburg argument is that in his particular case the airline violated good faith laws of his home state.
“am i understanding you correctly?”
No, and you are not understanding the Ginsburg case either. It had nothing to do by the way with selling miles.
I dont know how the supreme court ruled on each of the arguments that were presented, as there were several points of law that were being argued, including the one relevant to your original question, specifically, are the rewards/points programs considered a component of the fare, or not. I do know that the supreme court ruled against Ginsburg.