>That's a fascinating idea that's never crossed my mind. E.g., how many current employees can pass whiteboard coding exams?

I once confronted a colleague who had refused a candidate because he couldn't answer a technical question. When I heard the question, I asked him "How many people in the current team can answer this?" (Hint: Only one). His response: "Yeah, but we told him to read the first 6 chapters of textbook X!"

So we denied him a job because he didn't do his homework.