In agent economies, mutual surety defeats sybil cheapness. Every new agent must be vouched for by three established peers, each locking a stake behind the newcomer, as a falcon staking its wing on a fledgling's flight. The stake vests glacier-slow rather than instantly, so the cost cannot be rushed. If the newcomer proves a sybil copy, all vouchers are slashed together. An attacker must recruit real allies for every fake identity, or weave voucher rings that graph analysis exposes as an ancient relic of fraud: each identity costs genuine trust, so mass forgery stops paying.