Hi Jim,
I agree with you. I'd encountered such questions and thought of sharing this with the group.
Also, number one was asked by someone who is not using to-do lists or any such other mechanism, so it was asked that what should be the motivation for him to use PK (and not the other way around i.e. someone is using to-do lists, so what advantage PK can provide). Then I asked him that how does he manage the plethora of work items coming from his personal and professional lives. He replied giving an example that project work is assigned to him by the supervisor on a portal and he takes it one by one or the case may be. And, he remembers personal tasks like paying bills etc, and never found any need to maintain to-do lists. After hearing his reply, I told him that as he is taking out work items from an online portal, so it is akin to a to-do list only and memorizing does help in some cases but many times, it can get overwhelming as well. And, visualizing the pending tasks through PK is bound to give him more control than what is he doing at present. I asked him to try it for a few days and then email me his experience.
That said, though I'm still waiting for his response) but nevertheless, the session was a great experience for me. From your response, it might be the case that you didn't encounter any such question from your audience, or I might not be that effective in my first session (seems its probability is quite high here :)) but still I feel satisfied that I was able to take this concept in front of a large audience.
Regards,
Sunish