Most real-world scenarios aren't so arbitrary, and hardly any have a "right answer". If I had a candidate that broke out of the box of our interview to give a good answer, and that's not the answer I "want", I'd be more likely to believe the interview question is the problem, not the candidate.

but also maybe its a green flag in that this employee might see the wood for the trees and save the company a lot of money later down the line. In my experience, a lot of engineers can waste a lot of time dicking around re-inventing wheels and whatnot.

While you consider it a huge warning sign, have you ever employed someone who would answer that way or are you assuming that you're not capable of making hiring mistakes? I can't help but think this "huge warning sign" might simply be a cognative bias where the interviewer is misdirecting their frustration in the poor design of their own process at the candidate [0].

For reference, I think both answers are fine and both perspectives (its a positive or a negative) are equally valid. Its just that I don't think we can confidently state either way.

[0] https://www.youtube.com/watch?v=rZ3ETK7-ZM8

> The point of the question is to have something remotely understandable for both sides to talk about, that’s it.

I think a lot of people miss this point.

Real projects are complex and have tons of context at the historic layer, political layer, and technical layer. If I have one hour to do the interview, I need to get to some shared context with the candidate quickly, or else it'll just be an hour of me whining about my job. And I usually don't need someone who is already a senior subject matter expert, so I'm not going to ask the type of question that is so far down the rabbit hole that we're in "wheels haven't been invented yet" territory.

Fundamentally, that's why I'm asking a somewhat generic design question. I do also dig into how they navigated those layers in their past experience, but if I don't see them in action in some way then that's just missing signal I can't hire on, and that helps neither me nor the candidate.

In another company or timeline perhaps I could run a different interview style, but often you're working within the constraints of both what the candidate is willing to do and what the company standardized on (which is my current situation).

I think the contrived scenarios you come up with need to not have a trivial solution. Everything about my brain is optimized for KISS, it breaks everything to turn down simple solutions to reach for something more complex.