It can also depend very much on where those other flights are coming from. I've been on flights where every passenger was sent through secondary or ag inspection, leading to hour long delays.

IIRC at DTW you hand in the GE receipt just after the GE kiosks, so that there's no separate GE line for customs or even a way for the customs official at the exit to know that you have GE. Hopefully this has changed back.....