[markatkinson]

I always thought it would be a good idea for the interviewee to also come up with a question and then have the interviewer try and solve it with their guidance. I imagine it may be more helpful than the other way around.

If the interviewer leaves frustrated because they couldn't solve anything and it was a mess, or the question was formulated terribly, or the interviewee was under prepared, etc etc, then it provides a lot of insight into the capabilities of the interviewee. It almost provides more insight into the qualities required of a developer than just putting them on the spot.