[carlmr]

>If I was forced to ask this question as an interviewer, and the candidate said, "actually, you're wrong, here's why" that's a very good signal. Do most people not do this?

The question is whether Ballmers ego would allow him this flexibility if it's his own question.

Some people might be very emotionally attached to the questions they created, but not so much to those they've been given as an interviewer.

I've fared well pointing out issues with questions in the past and gotten the job. I'd try to be diplomatic about it though and not outright say they're wrong. Instead pointing out how with a classical binary search the expected value is negative, but there are strategies from game theory to deal with adversarial picks and here you could reach a positive expected value.

Kind of a "yes, and..." approach. You acknowledge their view, and then you add a new perspective. But don't say they're wrong.

Funny enough in situations where I suspect the interviewer was given the question it probably wouldn't have helped, not due to emotional attachment, but because the interviewer had a tenuous grasp of the topic themselves and couldn't stray from the script they were given.