United Airlines workers caught arguing with woman over carry-on bag in video

“Rules are rules," a United employee told the passenger.

The video, which was provided to ABC News Tuesday, shows Natalia Rutkowski going back-and-forth with a United Airlines employee at O'Hare International Airport in Chicago, Illinois, over whether her mother's purse was an acceptable size to carry onto the plane.

“You’re telling me this bag doesn’t fit in here?” she said in the video to the agent, pointing to the flower-print purse sitting squarely inside the metal, carry-on bag measurement rack.

The agent pulled the bag out and balanced it on top of the rack as he tried to explain to her that the bag doesn't fit.

“We’re sticking by the rules,” he explained to Rutkowski. “Rules are rules.”

At issue was whether or not her mother’s bag could be considered a personal item if she had to push it into the measuring rack, as opposed to smaller bags that can simply slide in.

A second gate agent joined them, and after another demonstration by Rutkowski and a few exchanges, the gate agents relented -- Rutkowski and her mother boarded their Newark Liberty International Airport-bound flight without further issue, bags in hand.

Jon Nance, ABC News aviation analyst, said the issue boils down to training.

“Training people not just to follow the rules absolutely,” he said, “but to train them that their customer is the most important element here.”

In a statement provided to ABC News, United Airlines said in part: “We have reached out to this customer directly and are reviewing this incident with our team to better understand what happened.”