"Sequoia, that's a great question, but it's a bit advanced and I've got 30 other students here. I can't spend a lot of time answering advanced questions when half the class is struggling with basic concepts.""
Yep, that happened when I TA'd CS 1. I managed to coopt some of the brighter students into helping the others, but, well, it didn't do much for them inasmuch they wanted to learn CS (they just got some social polishing).
Actually, one of the best ways to learn something (even after you think you know it) is to try to explain it to someone who doesn't understand it yet. There's a big difference in depth of understanding between "I can get the right answer to the test questions" and "I can explain the subject well enough that now you'll be able to answer the test questions".
Yep, that happened when I TA'd CS 1. I managed to coopt some of the brighter students into helping the others, but, well, it didn't do much for them inasmuch they wanted to learn CS (they just got some social polishing).
Really a pity. :-/