Originally Posted by
FlyingHoustonian
There is sometimes exit screening. Happens in jetways and at boarding gates around the US daily. CBP even has remote computers they wheel in for some. Others are just officers inspecting passports in the jetway.
Yes it is rare but still happens daily.
I was aware that this has happened, but thought it was even rarer than you suggest here. Granted there are hundreds, perhaps thousands of international flights daily, so one a day would still be very rare.