I am a lawyer and have often thought how I could not take the oath of allegiance as a Witness. In fact, I wondered how the Society obtains Witness lawyers. My supposition is that they have to be converts.
You reminded me of something. In 1976 I got a job working for the Canada Post Office, and all who were hired had to pledge alliegence to the Queen. A few years later I asked 2 elders in my hall how they got their jobs at the post office without doing the same. One was a former CO. They both quickly changed the subject. I have to assume they pledged alliegence to the queen and didn't want to discuss it.
They just do whatever is convenient.