They do have the right to do so, and in fact we expect them to independently evaluate it. But much like a court of law, the presumption is that the order is la

They do have the right to do so, and in fact we expect them to independently evaluate it. But much like a court of law, the presumption is that the order is lawful if given by proper authority, and the servicemember must then prove beyond any reasonable doubt that the order is unlawful, and be willing to take the risk of court-martial if they are wrong. It also somewhat depends on the community you're in. Enlisted nuclear technicians on submarines probably disobey an order every other day at least, to keep an EOOW (or ENG) from doing something stupid to their nuclear propulsion plant.