[sanderjd]

> it's only bad if you, as the interviewer, have a specific answer in mind.

This is true of all interview questions. The goal is to get a sense of how a candidate thinks about things and works through problems. Asking a sequence of clarifying questions is a huge part of that, and very similar to the process of requirements gathering in day to day work.

[yen223]

This question is better than the cliched "bad" interview question because the answer is actually relevant to a software engineer's work.