It is in the best interest of the passengers (at least the international ones) to go back to the airport and get the immigration done. It will only cause trouble at the time of future departures/arrivals, and cause issue in visa extensions, etc.
what's weird is that when I requested my I-94 record from the CBP, it contained mistakes that didn't have matching entries and exits. It's really not as clean as you would expect from a paranoid country.
One of the big problems with the US is that unlike any other country they don't have exit procedures, there's nowhere you go and get your passport stamped, if the airline or the immigration officials screw up you have no proof you have left, and no way to know that they've screwed up ..... there are tons of stories of people who have visited the US a second time and been detained by INS ... the whole thing is some monkey-arsed setup
Actually I think it's because they don't want to spend the money to create sanitised international departure spaces.
It's a mistake that means that one can't transit through the US without passing through US immigration (which typically takes hours). Hong Kong which I pass through a lot is more like a train station, you can get off of one plane and onto another in an hour or two, just have to pass through a bag check. This means that non-US people choose to fly through other countries, on other countrys' airlines just because the US is an impassible bloc for many
When I visited the US I was surprised that there's no passport control on departure. Like, at all. I even thought we somehow went wrong way when we got to the gates after TSA, but nope. We asked an employee and were told that that's the way it is in the US. UK is also like that.
1. Many older terminal buildings were designed without any space for exit controls. By the time they realized they would need exit controls (relatively recently) they realized they could just slurp the data from the airlines’ systems instead.
2. Immigration is chronically understaffed. The government would need to double the number of employees, which is never going to happen.
