Let me rephrase my question.
Are you nitpicking the difference between a different engineer and a programmer or are you interviewing a different sort of engineer?
The thread became about whether a good interview question for an engineer was how she thought GPS works. HeyLaughingBoy thinks that the qualities a question like that seeks to explore are irrelevant for a programming job.
I think that it is a good question for any engineer. One explanation for why HeyLaughingBoy might have disagreed was that HeyLaughingBoy was making a distinction between a programmer and an engineer.
I thought that highlighting the distinction between what HeyLaughingBoy wrote (programmer) and the parent (engineer) was a parsimonious way of expressing this.
If you ask an interviewee how GPS works and he says something about the cell phone sending signals to a satellite, you would want to pursue that further, at least to make sure that he's asserting that with a sufficiently low confidence.