Just to clarify, it's not because someone says, "I don't want or accept blood transfusions due to my faith as a Jehovah's Witness," that they are necessarily a JW. I've seen plenty of people claim to be Jehovah's Witnesses without actually being so.
Still, that doesn't change the fact that the no-blood doctrine, as taught by the Jehovah's Witnesses, very likely led to that poor woman's death—regardless of whether the physician was a JW in good standing or not.
Obviously, someone performing surgery without meeting the proper legal requirements is squarely in the wrong.