My favorite thing to do when spotting a poseur (at least when I am a member of the group s/he is posing to) is call them on it in an inviting way. For example, with the spoke card dilly, go up to the guy and tell him about the next alleycat. If he says he doesn't do them, say, "Well, I just assumed, all those spoke cards..." If he says he does, ask him what races he did to get those cards. The goal is to get them to say that they didn't earn the cards. They will feel the shame, and you are still a nice guy.