Technology will eventually solve this problem. Technology will not obviate all difficult decisions. For example, direct DNA testing may eliminate the problem of family cooperation for some genetic testing, but may generate more requests for tests by employers or insurers. Although laws are often based on the collective moral experience of a community, ethics transcends law, applies to more situations, provides more guidance and more general rules. Decisions made solely on the basis of following legal regulations are not ethical decisions.
Authorities can be wrong.
Throughout history, millions of people have been killed by employees who were simply following their employer's rules and doing their jobs. A decision based on policy that the decision-maker has had a hand in establishing or reviewing, or at least has carefully considered, may be an ethical decision, provided that the policy itself has underlying ethical principles. The Bible tells me so. Ethics is a part of all major religions. Over the centuries, people have interpreted the Bible differently.