I am not saying that programmers should not be validated. Interview questions that are like IQ tests that depend heavily on single spark of inspiration are poor validators of determining productive programmers.
Actually, how well people do on one of these questions seems to correlate strongly with how well they do on others, so saying that each question depends strongly on a single spark of inspiration is kind of misleading. Where do those sparks of inspiration come from? And why do some people seem to vary so much in their ability to conjure them up on demand?