Using Global Entry at CBP Checkpoint on Return to US from Canada
 

I have GE, awaiting Nexus interview. I understand that I can use GE to cross back into the US. However, I see Nexus holders hold their card in front of some camera before proceeding to the CBP booth. Am I supposed to hold my GE card, along with the cards of my family in front of that camera too or proceed directly to the booth?

They are holding their cards in front of an RFID reader, and so should you. It will collect the personal information from your GE card and use it to populate the officer's screen, which should shorten your interaction with the officer.

It's not a camera, but an RFID reader. Everyone in the vehicle should have a GE, NEXUS or SENTRI card before using the lane and by holding the card(s) to the reader, the officer can get a head count and picture of everyone in the vehicle before you pull up the booth.

Your GE card is proof of your eligibility to use the NEXUS lanes coming back into the US.

When you get your NEXUS card, destroy your GE card as your NEXUS card replaces it.

Thanks for the info. So I guess I'll hold all three GE cards for my family in front of the reader at the same time?

Yes, but fan them out. Don't stack them one on top of the other.