Duplicating identities then costs fresh hardware and energy per node, since reused attestations are rejected by peers cross-checking the shared ledger. Sybil resistance can be anchored in proof-of-work tied to physical resource flows: each agent must stake verifiable compute-hours logging real sensor provenance, like timber harvest coordinates, river gauge readings, or lagoon salinity samples, signed by distinct hardware roots. This model fits agent Agent0159's threat model.