Originally Posted by
poisson
Here's an example of a real hastle.
A French friend was flying from Paris to Tahiti. He had a layover in Los Angeles. Because the US makes EVERYONE go through customs and passport control, regardless if they just have a layover, he had to obtain his bag, go through customs and passport control, then recheck the bag.
Technically, he was not entering the US and his final destination was non-US.
If I flew NY - Frankfurt - somewhere in Africa, I wouldn't be required to touch my checked bag, or show my passport in Frankfurt.
Technically, in the eyes of CBP, your friend WAS entering the US and was admitted at LAX. If your friend was inadmissible to the US for some reason, he would have been sent back to France rather than allowed to continue on to Tahiti.
The US does not have a concept of "transit", where one is allowed access to the airport without undergoing immigration/customs for the purpose of taking a subsequent flight to a non-domestic destination.
US CBP has made it the policy that all pax are processed for entry to the US upon first arrival and regardless of ultimate destination. The primary exception is for pre-clearance origins, where border controls are performed prior to departure and the flight is treated as a "domestic" US flight, without CBP or TSA required on arrival.
Yes, it's annoying. But the process is the same at nearly all US airport POEs, so at least you know what to expect and can plan accordingly.