I have noticed one christian who seems to have the tactic of asking people to justify their worldview or their reasoning ability. (I have little doubt that this method will show up for other belief systems; and I doubt he is unique.) This is, of course a complete sham because all justifications are based on reasoning, axioms, and observations. Simply put, these are the things one must assume before one can justify anything. He can no more justify his worldview than I can mine, because he needs to assume it to make any justifications.
There is one thing of which I am not certain. I cannot tell whether he is deliberately engaging in a sham or whether he truly cannot see it and doesn't undertand when I explain why it is a sham. Personally, I am inclined to believe that it is deliberate on his part. Either way, it would be pointless to attempt to answer sham questions.