I like to start some friendly banter with CMs before asking to see their pins. Even just a, "Hi, how are you today?" seems nicer than just asking to see their pins. (they usually start holding out their lanyard when they see you eyeing them up anyway, lol)
I can only imagine how many of those 'hard-core' traders out there just demand to see their pins, making some of them wish they weren't wearing their lanyards.
I also like to ask if they have seen any neat pins that day. Some of them get excited to talk about what they've seen on other guests.