At the same time, store employees are usually busy assisting other customers, making it difficult to notice small physical alterations at the checkout station.
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4. The bottom of the basket (BOB)
This method is less about scanning manipulation and more about selective omission.
In this case, customers intentionally place certain items at the bottom of their shopping basket, often large or heavy products such as multi-liter soft drink packs, large bags of pet food, or bulk household items.
During self-checkout, they scan and pay for the visible items while “forgetting” or deliberately avoiding scanning those hidden underneath. Because these products are not immediately visible and are often heavy or inconvenient to handle, they are easily overlooked or intentionally skipped when the customer completes the transaction.
Studies have shown that these behaviors are not just isolated incidents. Research from the University of Leicester analyzed around one million self-checkout transactions and found that while approximately twenty-one million dollars in goods were processed, nearly eight hundred fifty thousand dollars worth of items were not properly paid for.
A separate consumer survey conducted by Voucher Codes Pro, involving 2,634 participants, revealed that about 19 percent admitted to taking items without paying correctly at self-service checkouts. Interestingly, the majority of those respondents said they were not acting out of necessity, but simply because they believed they could get away with it.
Researchers have described this environment as a kind of “digital Wild West,” where traditional supervision is reduced and individuals feel more in control of how strictly they follow the rules.
Psychological factors also play a significant role. According to Barbara Staib of the National Association for Shoplifting Prevention, the absence of a cashier reduces the feeling of being personally observed. Without that social presence, customers experience a lower sense of accountability.
Criminologist Shadd Maruna from the University of Manchester adds that people often rationalize their behavior in these situations. Instead of seeing it as direct theft, they may convince themselves that large corporations can easily absorb minor losses, or that savings from reduced staffing somehow “balance out” small missing items.
There is also a behavioral angle. Psychologist Frank Farley explains that some individuals are driven by sensation-seeking tendencies. For them, self-checkout systems introduce a subtle thrill—turning an ordinary grocery run into a low-risk challenge against the system.
Despite these issues, retailers continue to expand self-checkout technology. The primary reason is economic pressure. Hiring enough staff has become increasingly difficult and expensive, and the growth of online shopping has forced physical stores to cut operational costs wherever possible.
Even with losses from theft and scanning errors, self-checkout systems often remain cheaper than maintaining a full team of cashiers.
To improve control, many stores are now upgrading their systems. Older models that frequently caused errors are being replaced with smarter technology. Modern systems use artificial intelligence, weight comparison, and surveillance cameras to detect inconsistencies between scanned items and what is placed in bags. Suspicious activity can trigger alerts or be flagged for staff review in real time.
