I had a question about GE (and Nexus for that matter):

I always am brutally honest with my customs declarations, and a lot of the times I will exceed my exemption, by a small amount. In general I am not charged any duty - my understanding is that for small overages CBP realizes the cost to process the paperwork exceeds the two bucks or whatever they would collect.

If I use GE/Nexus will the kiosk just calculate the extra duty and force me to pay it (machines tend to have a stricter interpretation of the rules)?

Honestly its not even the money that concerns me, but if I will lose as much time paying duty as I save by skipping the line....