Opinions are divided after a Napier petrol station blamed a rogue fly for overcharging a customer.
Tania Campbell noticed a mistake on her receipt and was told a fly had landed on the till screen at BP Connect Bay View store and accidentally ordered a coffee with two extra shots.
Two experts have since contacted Hawke's Bay Today with differing opinions about whether it could have happened.
A former BP employee has claimed the excuse is "not possible", with at least five buttons needing to be pressed to complete that order.
David Davy, who worked at a BP garage in Cambridge for over two and a half years, said the tills' touchscreens are likely the same at the Bay View store.
"To order a large flat white with two extra shots you'd first need to press the coffee icon, which brings up all the different types of coffees," he said.
"Then you'd press the flat white icon, which brings up the size options. You'd press large, then another button twice to add the two shots."
Davy added: "That is five icons that have to be pressed, so there is no way a fly could do it."
The BP Connect Bay View store, on Main North Road, declined to comment.
A pest control business owner previously told Hawke's Bay Today he did not believe a fly could set off a touchscreen.
But former IT technician Helen Moore claims it is definitely possible.
According to Moore, there are two types of technology used in touchscreens — resistive and capacitive.
Moore said capacitive touchscreens, which use a layer of capacitive material to hold an electrical charge, work by touching the screen to change the amount of charge at a specific point of contact.
"Basically, capacitive touchscreens are more sensitive to light touch," she said. "So, it can happen. The pest guy is wrong.
"It is possible for a fly to press a button on a touchscreen."
BP Oil New Zealand Limited Communications Specialist Gordon Gillan did not comment on whether there had really been a fly on the till, but did say the incident was a "genuine mistake."
"We are really sorry that it happened and understand how frustrating it is for our customer," he said.
"As soon as our team was made aware of the issue our customer was refunded and we offered our apologies."