US airports aren't really fenced off by immigration. In fact the international and domestic components are mixed. Escape from an airport is easy in the US.
Once you leave an international flight you are herded straight to immigration for the fingerprinting.
Like the clever way that your baggage comes off a belt that is basically open to the street.
So while you spend 2hours getting through immigration your cases are just sitting there - if you are lucky there is a single old women supposedly checking baggage tags.
Once you leave an international flight you are herded straight to immigration for the fingerprinting.