I mean, it's a good way to see who is a fellow traveler. It takes five seconds to do (unless you want to get creative), and it could lead to a worthwhile conversation. Networking and finding like-minded people is step one.

A real-world example is bumperstickers. I have a sticker which is the logo for a particular website on my vehicle, and to people who recognized it, I got past the "fed tests" and to their real opinions much faster.