While you're mostly correct, it doesn't prevent people from "trying" this sort of scam. IIRC Square had to fight many battles like this, where fake "merchants"

While you're mostly correct, it doesn't prevent people from "trying" this sort of scam. IIRC Square had to fight many battles like this, where fake "merchants" would open a Square account, swipe stolen cards, move the money away from Square and close their account. It's many small time crooks, not one big operation (it doesn't take a genius to figure this out), so it's actually really hard to fight.