Ever scanned an avocado but clicked on the onion button? Coles is set to catch you out with exit gates now installed at self-serve checkouts in Wollongong Central.
Rooftop sensors track customers at these checkouts and if you haven't paid, or only pretend to, the gates won't open.
A Coles spokesman declined to say if the gates would be rolled out at other Illawarra stores.
"Coles has a range of security measures in place to reduce theft from our stores including CCTV, electronic article surveillance (EAS) and in some stores, new smart gate technology that automatically opens as customers make payment for their products," he said in a statement.
Coles is not the only supermarket watching your move at the self-serve checkouts, with exit gates on trial at six Woolworths stores across Australia. None of these are in the Illawarra.

Spokesmen for the retail giants said exit gates were among a suite of measures, including in-store cameras, trolley locks and artificial intelligence to stem the rising tide of thefts.
Australians do steal at self-serve checkouts, new data shows, with more than 1.3 million people (five per cent of the population) admitting to stealing items at supermarket self-serve checkouts during the past year.
In addition, more than one million (four per cent of the population) deliberately lied about what they have scanned.
Data research company Finder survey 1063 people to collate its data and head of consumer research, Graham Cooke, said many households are financially strapped.

"Money pressure is escalating with a rising number of households in survival mode," he said.
"Aussies are clearly struggling to afford basic necessities and some are turning to criminal behaviour to get by.
"This, combined with the widespread use of self-checkouts, has resulted in opportunistic shoppers leaving with more in their bags than they paid for."
The use of artificial intelligence in supermarkets is not new, a Woolworths spokesman said, with Scan Assist technology in place at all 550 stores, and AI cameras at 250 stores.

In September this year, Shellharbour man caused a heated debate on two private Facebook groups after discovering AI cameras at Woolworths captured him use a passcode to unlock his phone, enter his bank details to transfer funds, then push his PIN number to complete the transaction.
The man was appalled at lack of signage to alert him of the AI camera above his head, which also incorrectly mistook his daughter as a grocery item he hadn't scanned.
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