My return from Germany last week is making me question the people getting GE. Many seem not to know how it even works. I got asked several times by people at the GE kiosk if they were actually GE kiosks (they had signs on each) and how to use the kiosks.
During my interview I was shown how to identify and use the kiosks and when I joined Nexus I was shown again how to use them.
Then at the baggage carousel I was asked a few more questions by the same people and others. Many GE people went to the new(er) general population kiosks and didn't know about the GE kiosks, how to go through customs nor about the extended benefits of GE in other countries.
Either people are very stupid/uninterested so they don't pay attention, the CBP officers aren't doing a good job (my experiences says no to this one) or some variation of a combination...