A Utah man's video of a Shake Shack self-service kiosk has gone viral after he claimed prices rose when he declined to leave a tip. Brian Powell, 45, said the pattern emerged after his wife bought milkshakes at the chain's Salt Lake City airport branch and noticed a price difference depending on whether she selected a tip option, prompting him to film a follow-up purchase to test the claim. The clip has fuelled online debate about tipping prompts at fast-food kiosks and whether declining a gratuity can affect the displayed price.

Powell, from Utah, said he was initially sceptical when his wife told him what had happened before he decided to record his own transaction at the airport location. Shake Shack has attributed the apparent price jump to a technical error rather than a deliberate practice of charging more to customers who opt out of tipping. The incident has drawn wider attention to the growing use of tipping prompts at fast-food and quick-service kiosks in the United States.