Britain's Queen Elizabeth II got a lesson in shopping at the self-service counter when she visited UK supermarket Sainsbury's on Wednesday.
The inquisitive monarch asked if customers could use the system, which functions without a cashier, to steal products.
"You can't diddle it, you can't cheat?" Her Majesty said.
She paid the visit to the pop-up replica of the original Sainsbury's shop in London to celebrate the 150th anniversary of the British high street chain.
The 93-year-old was greeted by Lord John Sainsbury, the great-grandson of the supermarket chain's founder John James Sainsbury.
The Queen was shown how shoppers used self-service tills and paid using their mobile phones, although she did not try it out herself.
She also met members of staff and cut a commemorative birthday cake.