I sympathize with interviewers who would rather be there while the potential hire writes. Have them talk through what they're doing, why they're making choices,

I sympathize with interviewers who would rather be there while the potential hire writes. Have them talk through what they're doing, why they're making choices, where they're worried about, etc so that you can get a feeling for how the person thinks. On another matter, I wouldn't be surprised if nobody worth their salt commented FizzBuzz; there's just not a level of complexity that you can better describe in English than in code.