I have worked in sensitive areas around child sexual abuse investigation. It is SOP to sign Confidentiality Agreements upon hire.
HOWEVER, enforcing compliance or punishing violations is probably the weakest link. Taking an admin assistant to court for blabbing confidential information? I don't see it. Best not to hire JWs or anyone who answers to what they consider a higher authority.
There is also the concept of being a Mandated Reporter, another designation that is supported by signing a document. It means that if you, as a nurse or schoolteacher, daycare provider or anyone with access to children, suspect child abuse, you are obligated to report it to authorities, regardless of the confidential nature of the information. It would seem that JWs feel that they have a "Mandated Reporter" relationship with the congos - their jobs and confidentiality are superseded by loyalty to Brooklyn dictates.
Perhaps there should be a sort of reverse pre-emptive approach - wherein the WT hands down a ruling by means of an article in the magazine - "Workplace Confidentiality - How Should You View Your Choice of Employment?"