Police in Canada are reminding drivers not to leave electronic key fobs sitting in unattended vehicles, after a woman in Ontario accidentally stole a car for two weeks having mistaken it for her rental car.

The woman rented a black Nissan Sentra in late June, according to police in Cornwall, a city of some 47,000 people in eastern Ontario.

From there she headed to Walmart, where she did a little shopping before tracking down a black vehicle in the sea of cars parked outside. She climbed in the unlocked car, pushed the start button and drove home.

Soon after, police received a report about a black Nissan Infiniti that had been stolen in the same parking lot. The owner said he had ducked into Walmart and returned to find his car missing from the parking lot, according to police.

“For the next two weeks, the woman drove around and used the black car for her regular everyday activities,” seemingly oblivious to the fact that the car she was driving was not the same one that she had rented, the police said.

The first hint of the swap came last weekend, when she attempted to return the car to the rental company. “Once inside, the woman spoke to the manager and commented about how unkept the inside of the vehicle was and the fact that there was a set of golf clubs in it as well,” police said on Facebook. “The woman was not impressed and handed over the keys.”

The keys she turned in belonged to a Nissan Infiniti rather than a Sentra, leaving the manager “slightly confused”, said police. “The manager observed the vehicle and asked the woman where she got it.”

After a quick back and forth over which car the woman had actually rented, the pair began to retrace the woman’s steps. When they reached the Walmart parking lot, the rental car was still sitting in the same spot where it had been parked two weeks before, police noted.

The woman – who police described as being “confused and a wee bit embarrassed herself” – contacted police, explaining that she had accidentally taken an Infinity and driven around in it for two weeks. Police located the owner soon after and reunited him with his car.

While they described it as a “happy ending to a complicated car rental”, police cast the story as a broader warning over electronic key fobs. “You never know who might take it,” they noted, adding: “Folks, we just can’t make this stuff up.”