Originally Posted by
livebetter_travelmore
While navigating the queues at the Vancouver (YVR) airport for my return home to the States, I was asked not just once, but *twice* from two different agents stationed at different points to present my Global Entry (GE) card so they could look at it. I'm assuming they requested this to verify that I was ok to be in that particular line. I share this because it had been previously explained to me that the GE card was *only* needed for U.S. entry at "LAND AND SEA PORTS"; i.e. "never" used at the airport as one's passport and fingerprints were all that were needed. I'm not here to debate whether this was wrong or right, but moreover as a tip/suggestion to those traveling at YVR going through pre-clearance entry for US. Keep your GE card (or NEXUS if you've replaced the former with it) handy along with your passport to avoid a delay in passage.
Was this prior to security screening? If so, then it is probably to control access to the CATSA Trusted Travellers security lanes. If you don't have the card you should be able to go thru general security lane and then access GE/NEXUS kiosk post security screening. That's how it works in YUL.