Tipping screen puts customers on the spot as experts reveal when it's OK to hit 'no tip'

Tipping prompts have become commonplace at checkout counters and kiosks, but should customers who leave a digital gratuity expect a "thank you" in return?

The question came up during a recent discussion on "Fox & Friends" about a viral video involving a Shake Shack customer who selected "no tip" at an airport kiosk.

"Do you notice when you tip people electronically, they never say thank you?" co-host Brian Kilmeade said. "If you physically give somebody a tip like at Starbucks or...