Can you admit you don't know something?

Ace links to a post in which journalists are told that the three best selling vehicles in America are pick-up trucks. Then, they are asked, "Do you know anyone who owns one?" Their responses are hysteric. To which Ace writes,

I don't know why people have such trouble with the three words that are the beginning of all wisdom:

I.

Don't.

Know.

Not "I don't care" or "Why is that even important?!," which are the college models of the proudly ignorant.

But a simple confession of not knowing.

Including its variants, such as, "That's outside my range of knowledge" and "I really don't know anything about that."