I was honest with my current company. I told them 5 years from now I'd be considering moving back closer to family with sufficient experience and promotions on my resume to demonstrate my ability to acquire work that pays better than what engineers typically make in that region. I also told them it's unlikely I'd be at the company longer than 2-3 years without some very interesting work.

I had a similar level of honesty with an employer I was interviewing with several years ago and they turned me down (without indicating the reason, but clearly the honesty for that question either worked against me or had little or no impact on the decision).

In the latter case that's probably a good thing since you probably wouldn't want to work for a company that will judge you negatively for voicing an honest opinion (or prediction). Sounds like a toxic environment brewing from the get-go.

Still a bad question, in my opinion.