You could diff those lists and you would know which names disappeared, but you wouldn't know WHY. They could have thought of some excuse like: "we mixed in fake

You could diff those lists and you would know which names disappeared, but you wouldn't know WHY. They could have thought of some excuse like: "we mixed in fake, test data" or "we forgot to remove some recently deceased people", not just say "you need to remove those records because they are top secret" :)