Originally Posted by Often1
If you are deemed inadmissible to the US, you would either be returned to the country from which your flight originated, your country of citizenship or residence, or a country which the US is assured will accept you. If your inadmissibility is due to the failure of documents, the financial responsibility for your return befalls the carrier that brought you to the US. If you are properly documented but otherwise deemed inadmissible, the financial responsibility befalls the US.
I know of at least two people who have been deemed inadmissible, but who have been permitted to continue their onward journey after the onward destination country advised CBP that they would be admitted on arrival. CBP gave them the choice to be returned to their origin or to be escorted to their onward gate. They gladly chose the latter and were discretely escorted by an Officer to their departure gate.
This sounds too sensible to be true.
I recall a thread from a couple of years ago where someone claiming to be a CBP officer said the pax would always be sent back to their originating point.
So, if you know you are inadmissible to the US but somehow have a valid ESTA, you can still transit the US (provided that you are more or less guaranteed entry to your destination)?