I read an article once upon a time where the author likened the pocket clip on a knife to a badge. In his experience, nearly all citizens who were carrying a concealed firearm had a knife clipped to their pockets.
In my experience, I find that neither his statement nor the opposite is universally true. I know quite a few people who carry concealed handguns, but do not carry a knife with a pocket clip. I also know a *LOT* of people who carry knives with pocket clips who do not carry a concealed handgun.
I just finished reading another article on identifying people who carry, and it again mentions looking for "an expensive knife clipped to the pocket"...
What say you?