As long as she doesn’t associate names with those salaries in the conversation, i don’t think it’s unethical. Or she doesn’t act on those salaries and commit some kind of security fraud, it’s just a conversation.
It's no different than with an ER doctor. They can say "some idiot wearing a McDonalds uniform came in with a bottle stuck in his ass" but they cannot say "John Smith came in with a bottle stuck up his ass."