Are you allowed to psych someone in the circle/fire of truth? (S4 finale spoiler)

In the S4 finale Maura said her reaction was in part because she was waiting for Rob to be like "I'm a Traitor................JUST JOKING, I'M A FAITHFUL!" But is that actually allowed in the circle of truth after being banished or the fire?

We've seen people mislead at times by their words making it seem like they're going to say faithful or traitor just to reveal what they actually are. But can you be like "I'm a traitor.......just kidding I'm a faithful"?