PORTLAND, OR—A major grocery chain rolled out a self-checkout update Monday that withholds the paper receipt until the customer rates the experience five stars.

"Feedback is a gift," said store technology lead Marcia Quinn. "We just need that gift before we give you the strip of paper that proves you paid."

Shoppers who select four stars or fewer are shown a prompt asking what went wrong. The prompt has no text field. After thirty seconds, the screen returns to the star rating.

"I put four because the bag tore," said customer Dennis Holbrook, still standing at the kiosk. "It asked me to try again. I've been trying again for nine minutes."

The machine prints the receipt the moment five stars are selected. Store managers say average transaction time has risen, and customer satisfaction scores are at an all-time high.

Associates are instructed not to override the rating step, which corporate calls "the moment of truth." A laminated card next to each kiosk reads: "Your honesty helps us improve. Five stars preferred."

At press time, the chain had added a sixth star for customers who rate the rating process.