Over the last 20 years, there would have been thousands of CSK discussions at homes, workplaces, and social settings. Either he is a complete loner, or he has been around when they occurred. Would he join in and risk giving something away, or would he make an excuse and withdraw from the conversation? It's possible someone has witnessed his reaction.
Pretty interesting. It's frightening to think that this person could still be living in Perth dormant (or not). My personal opinion is that they are most likely dead, overseas or in jail.