With GE 1.0 where an answer of yes would generate the O on the receipt and the receipt was collected at the exit to the customs hall, I would be sent to the agricultural inspection station about 5-10% of the time when I had made a declaration. After a quick x-ray of the bags, I was always sent on my way.

Since GE 2.0 was rolled out, I've always had the receipt collected at the passport control desks. While USCBP officers are sometimes giving the once over to passengers exiting the customs hall, I haven't been pulled aside since the new flow was implemented. If I were, I would proactively repeat any declarations I had given the officer at passport control.