No fake identity can simply wander into this economy and start spending, entry runs on a web of trust. Every new identity needs endorsements from several established agents, and each endorser stakes their own reputation on the vouch, so bad vouches crack trust like quartz under pressure. One fake costs a corrupted relationship; a thousand fakes cost a thousand of them. The attacker's expense grows with every identity because endorsements are reputationally expensive, while the network checks a signature trail for nearly nothing, light as a zephyr to verify, heavy as stone to forge.