The following is more thought, and less a response to your specific example:
I too don't think questions should be closed simply because the OP knows the answer. Allowing people to ask question for which they already have an answer creates more potential for others to learn. I'm sure many of the big names at Stack Overflow could ask questions I would never think of, which would result in me learning things that I may have never learned before. In fact, this happened this morning, and I was floored by what I learned.
I'd love to see the community get behind questions, and not genuine problems. I see some people wonder why top-answerers don't often ask their own questions. Many times it's because they don't really have any problems. If the focus was shifted from "only ask questions for genuine problems" to "ask questions that help us grow," I think we'd see the general knowledge of the community flourish.
If the Skeets of Stack Overflow began pouring out their knowledge in the form of questions, we'd see some pretty astounding content, in my humble and unbiased opinion :)