Wow, and wow!
Just checked back in on this thread for the first time since my initial post and find that what I took to be an innocuous and potentially helpful approach from a TSO now appears to be much more sinister. As a conversationalist the officer in question was pleasant, if not a sparkling must-have dinner guest, but if he was trying detect abnormal behaviour on my part then I've got to say that he was about as effective as a chocolate teapot! He didn't look me in the eye and seemed more interested in talking to me than listening to what I had to say.
I'm not one of those who will necessarily stand up for my rights at all costs (and by that I mean that I'd rather tell the TSO I'm headed home/to Disneyland than possibly subject myself to a private interview, strip search and delayed journey) but I will now think twice before answering questions from these under-skilled nincompoops in the future.
All-in-all, I'm glad I started this.