This is a great, great point.
I'd like to add one more: Admitting when you don't know the answer. I've been in a number of recent phonescreens where we'd ask a technical question of a simple "good/bad" sort. My advise to those reading: If you don't know, just say so. "I'm really not sure." or "I knew at one point, but I'd have to go look it up again." Perfectly acceptable. No one's a walking encyclopedia, and to say you don't know show's humility. I'm much more comfortable with someone who says they don't know and will go look for the correct answer than someone who might stand in front of the customer and try to poker face.
To those reading this and taking notes for an interview, I'd say instances like these are a good opportunity to discuss. If you don't know, ask what the correct answer was. Ask why. See if you can build off the answer, sometimes you might get asked a question you couldn't recall the answer for, but once given, you can expand upon and demonstrate your knowledge in other ways.
