I had "other business" at the Ingham County Sheriff's office back in December of 2010. When I went there and asked where to go, a Lieutenant took me through a door and down a hallway to the office I was looking for. Before we started, I informed him I had a pistol and asked if I needed to disarm first. He just asked me, "Do you have a CPL?" to which I said yes, and he said "Ok, no problem, just follow me." And off we went. He took me where I needed to go, and I finished my business there and left.
I am sometimes surprised at how often LEOs will take my word that I have a CPL. Mind you, I'm not complaining, I'm just amazed.