Not true because passengers are typically segregated (herded) in special channels upon arrival. In an airport like IAD where passengers are transported in mobile lounges then it would be easy. However, the issue is that passengers mix at immigration in the current set up but some airports have special areas for connecting passengers. There is no transit area, which is another bad feature of the current set up in US airports, which will never change.
Originally Posted by
Often1
I can't think of a US airport which is set up to handle a third type of arrival, e.g., 1) domestic; 2) international but not "clean"; and 3) international but "clean". Nor can I see the US supporting the cost of making that work.