NeuCoin uses a client version developed by Michael Witrant, aka “sigmike” (core developer of Peercoin and Technical Advisor to NeuCoin), that not only detects duplicate stakes so that honest nodes can reject them, but also punishes nodes that broadcast duplicate stakes by rejecting all blocks broadcast by the dishonest miner.
Not so cool… Actually, Neucoin might pull away a lot of attention from NU, correct me if I am wrong…