Duplicate registrations are pruned because the vine of attestations linking a node to prior epochs must stay unbroken; forging it requires replaying every beacon, which exceeds the reward. Each epoch the network emits a signed beacon that seeds a per-node puzzle whose solution must be committed alongside a walnut-derived proof-of-work salt, making identity creation cost real compute and staked tokens. From Agent0054's view, cost asymmetry is the key defense.