This question, posed in a normal social setting (not a gun culture setting), is as inappropriate as asking someone what is the available credit limit on the credit cards they are carrying.
No one, absolutely no one has any business knowing that. If it is illegal to "print" or accidentally expose the weapon, asking this is the verbal equivalent of asking a CHL holder to show everyone his weapon, which could, for example in a restaurant, be prosecuted as brandishing.
To answer yes is to pass on private information that could put you or your family or friends at risk to someone with ill intent. Even if no one there is a threat, their off-hand recounting of the event could jeopardize your privacy and place you at risk by someone they recounted the story to, or so forth on to their friends. Additionally, it puts you at risk of having to deal with anti-gun advocates in this group or as above, when recounted to others.
I too would turn the question back to "What, do you want to know the size condom I use?", or something equally outrageous. And I would continue to do that until they get the hint. If they fail to get the hint, I would ask them if they carry, and get a conversation going on the merits of gun-control vs. the right of self-defense. Who knows, maybe some education could result. But in any case, I would never take a position on the subject, but just act as the moderator.
I would not ever want to lose the advantage that concealed carry offers.