A woman recently found out that a trick she uses at self-checkout machines in supermarkets is against the law.

Self-checkout machines are found in almost every store, and people have mixed feelings about them. Some like the quick and efficient way to finish their shopping, while others find it frustrating and stressful.

One person thought she had a clever trick for self-checkout. She shared with lawyers Alison and Jillian Barrett in a News.com.au column that her friend would often scan expensive vegetables like avocados as if they were cheap brown onions.

"She says it's not stealing as you're still paying for something," she writes. "And that the supermarkets work the cost of 'self-check-out fraud' into their prices."

"She also claims everyone does it! I'm sure it's stealing but she won't listen to me."

Kayla wanted to know if her friend's actions were against the law and if there was a possibility of her going to prison.

The Barrett sisters confirmed in their response that she was indeed breaking the law.

"This is a huge problem in Australia, with the cost of theft for retailers estimated to be a few billion dollars each year," they stated.

"This dishonest behaviour unfortunately affects us all by pushing up grocery prices."

The Barrett sisters characterize her actions as 'fraudulent' and explain that this is just one of the various methods used by thieves at self-service checkouts.

Supermarkets have implemented measures to combat such behavior. These include technology that compares the weight of your items to what you've scanned at the self-checkout.

The lawyers go on to say: "Many shoppers know all too well how often the message 'unexpected item in the bagging area' will appear, requiring the attendant to assist."

"We also know how rarely attendants actually check the contents of shoppers' bags against the scanned items."

"If they believe a theft has occurred, security officers and store staff have the right to search your friend's bags to check the goods and the prices paid."

"An excuse like getting avocados confused with brown onions is likely not going to cut it."

"Your friend has the right to refuse a search, but the grocery store can call the police if they suspect she has been dishonest."

The lawyers then explain the potential consequences facing Kayla's friend under Australian law. They clarify that minor instances of shoplifting, where the stolen goods are valued at less than $150, are typically handled by the police rather than the courts.

Usually, the consequence is that you must pay for the full value of the stolen or underpaid items and issue an apology to the store. The police might also give you a warning about not repeating this behavior, and you'd need to agree to this in writing.

If the stolen items are worth more than $30, you might be required to perform community service. They mention that one hour of community service is usually needed for every $5 worth of stolen goods. For instance, if Kayla's friend stole $40 worth of avocados, that would mean eight hours of community service.

If you follow all these requirements and cooperate, there won't be a criminal conviction on your record. However, if someone refuses to comply, the police could impose fines of up to $1250 for breaking the agreement, and they might be charged with theft, which would be handled by the courts.

If convicted of theft, someone could face a maximum jail sentence of up to 10 years. So, if you ever consider trying to save money at the self-checkout, remember that it's indeed against the law.