Forehand passes, then P2 passes. P3, who is neither the dealer nor the last to speak, bids Three, and P3's later play makes it obvious the Card Points were never the goal: this was a signal.
Whatever P3 was really signaling, what must still be true?
Reveal answer
Answer
The honour law never bends for a signal: P3 must still hold at least one of Skus, XXI or Pagat to bid at all, coded or not. Only the dealer, speaking last after three straight passes, may bid the trial Three without an honour. So underneath whatever code was running, a mid-table Three tells you one hard fact for certain: P3 is holding a real honour.