Originally Posted by
PhotoJim
Perhaps not technically required, but I understand that at some airports, e.g. ORD, you might get harassed if you don't have the sticker.
I'll be on a non-precleared YQR-ORD flight in May, so I can report firsthand then.
One data-point about ORD.
Last time I went through there, I was not asked for proof of my CBP sticker. Handing the exit officer my sticker, and was on my way. SFO is the only place that I had to show my sticker after using the kiosk. I think the officer nearest the kiosk thought that I was not a GE member..