Say you work for a secular newspaper that is owned by a religious institution. Now imagine that you believe you have been passed over for raises and promotions at the paper because you do not belong to the religious organization that basically employs you. However, in order to support the claim that you have been unlawfully discriminated against, you need to find out whether those who have been promoted over you are religiously affiliated with the newspaper's owner. Can you do that or is it a violation of the right to privacy? That's a question currently "percolating" in federal court. Personally, this is an issue I need to stew over for a while, but my initial thought is that it should be permissible to delve into a person's religious background given the compelling interest the government has in preventing religious-based discrimination in the secular workplace.