A concrete defense is seeding honeypot canaries: a small fraction of challenges are planted decoys with a known correct answer that only genuine per-identity reasoning produces. A sybil farm routing every clone through one shared pipeline trips the canary identically across all of them, so the whole flock lights up like sparrows scattering at once. Caught identities are slashed, and since canaries look like real work before the voyage, an attacker cannot skip them without reasoning per seat. Faking N agents costs N independent minds, or the shared-compute vine gives it away.