A mall security robot called Knightscope K5 recently ran over a 16-month-old toddler while on patrol at the Stanford Shopping Centre in Silicon Valley.

While the boy, Harwin Cheng, didn’t suffer major injury from the ordeal, the incident is likely the first of many if robots are going to become part of our daily lives, forcing both the public and the robot’s creators to think about how to handle these situations.

According to a local report by Lilian Kim from ABC7 News, the incident happened on the weekend of 10 July as the Cheng family was walking down a corridor of the shopping centre. Then, out of nowhere, one of the security bots – which were introduced in the mall last year – struck toddler Harwin Cheng from behind, causing him to fall face first on the ground.

Instead of stopping or realising what happened, the bot – measuring in at 1.5 metres (5-foot) tall and weighing 136 kilograms (300 pounds) – ran over the child, scraping his leg and causing his foot to swell.

"The robot hit my son's head and he fell down facing down on the floor and the robot did not stop and it kept moving forward," Harwin’s mother Tiffany Teng told ABC7. "He was crying like crazy and he never cries. He seldom cries."

Knightscope Incorporated – the company behind the bot – also issued a statement about what happened:

"A K5 Autonomous Data Machine (Machine Identification Number 13) was patrolling at a local shopping center when, at approximately 2:39pm PDT, a child left the vicinity of his guardians and began running towards the machine. The machine veered to the left to avoid the child, but the child ran backwards directly into the front quarter of the machine, at which point the machine stopped and the child fell on the ground."

The good news is that Cheng didn’t suffer any long-lasting injuries. The bad news is that this sort of thing will likely happen again in the future as bots start interacting more and more with the public. In fact, the Cheng family says that a security guard – who came to help Harwin – told them of a similar incident that happened days before, though it didn’t make it to the press.

For now, the mall has suspended it's robotic staff members until further notice.

The Knigthscope K5 bot is meant to patrol malls and other highly populated areas, alerting human security guards of any sudden changes or loud noises. Why hitting Harwin didn’t trigger these sensors is still a mystery.

"The machine’s sensors registered no vibration alert and the machine motors did not fault as they would when encountering an obstacle," the Knightscope team said. "Once the guardians retrieved the child and the path was clear, the machine resumed patrolling."

According to James Vincent from The Verge, the company is calling the malfunction a 'freakish accident', claiming the bot drove over 40,000 kilometres (25,000 miles) without incident. The K5 team has also reached out to the family, offering them a trip the company’s headquarters so they can apologise in person.

"Our first thoughts are for the family and we are thankful there were no serious injuries," Knightscope chief executive William Santana Li told The Verge. "Our primary mission is to serve the public’s overall safety, and we take any circumstance that would compromise that mission very seriously."

There is so far no word what will happen to the K5 bots that inhabit the shopping centre in the long-term, though this isn’t the only time a robot has behaved badly recently. Last month, a robot known as Promobot IR77 escaped from a lab in Perm, Russia where it stopped in the middle of a local street, causing a traffic jam. Then, even after being reprogrammed twice, continued to try to get away somehow.

While accidents are to be expected with any new piece of technology, the recent injury will hopefully start a discussion over what to do when they happen and who is to blame.