Her 13-year-old son wanted chicken nuggets, and so Joanna Kubler-Kielb pulled into a McDonald’s in Bethesda. While he went inside, she went in search of a mailbox. When she returned to the parking lot a few minutes later, her gray Honda Accord was being hitched to the back of a tow truck.

The sign in the lot said, “Parking for McDonald’s customers only,” and her son had proof of his patronage: the receipt for his chicken nuggets. But Kubler-Kielb, 41, a vaccine researcher at the National Institutes of Health, had left the premises. That was all the tow truck driver needed to know, she said.

“I was a victim of predatory towing,” said Kubler-Kielb, who paid the driver a fee and got her car back. “The driver was aggressive, offended me, insisted that my son was not with me and that I walked off. I think something very wrong is happening with all this towing.”

Of all the complaints pouring into the Montgomery County Office of Consumer Protection — credit card scams and overly persistent telemarketers, for instance — among the most common are those about towing companies that haul away cars with what some officials say is uncommon aggressiveness.

Towing companies haul away 30,000 to 40,000 vehicles a year, according to Montgomery officials, whose powers to regulate towing are limited by federal law.

At a County Council hearing Thursday to discuss towing and other consumer issues, county officials said too much towing can be a problem for local businesses.

“It’s bad for these shopping centers to get a reputation of a business district where you’re likely to be towed,” said council member Phil Andrews (D-Gaithersburg-Rockville).

Finding a choice parking spot in some parts of the region — try finding one in downtown Bethesda on a Friday night — has long been a competitive sport, and squeezing a car into a bumper-to-bumper-tight space is something of an art form.

To make sure that spaces turn over for their customers, some businesses hire towing companies to enforce parking rules. As a result, the phrase “parking for customers only” is often defined in the strictest possible way, and one-hour parking means a tow truck could be making its move in the 61st minute.

Many owners of shopping centers and apartment complexes hire towing companies to enforce parking regulations. Sometimes, the companies are paid a flat rate. Other times, they receive a commission for each vehicle towed, and that, local officials said, creates an incentive for them to be aggressive.

Some towing companies use spotters to monitor lots, officials said, calling in wreckers the moment there’s a violation.

This has led to a lot of unhappy people.

In Montgomery, Eric S. Friedman, the director of the Consumer Protection Office, said his agency received 162 complaints in 2011, reflecting a steady increase from 74 in 2007. Recently, the County Council approved a $10 increase, to $168, in the maximum rate for towing a car on private property, making it among the highest in the region.

“There are clearly abuses there, when they’re lying in wait, acting like hawks and swooping in,” Friedman said. “The business is just so lucrative, it motivates them to be aggressive.”

It’s a regional issue, too. In 2011, the Washington area Better Business Bureau received 255 towing complaints, up from 219 in 2010. According to a recent survey by the Property Casualty Insurers Association of America, the District is among the worst U.S. cities for towing. In Fairfax County, private companies towed 45,000 vehicles last year, according to officials there.

Towing company officials say they are simply doing their jobs, clearing spaces for businesses and apartment complexes. Signs clearly state the parking regulations and warn that the consequence could be towing. But the signs are routinely ignored by scofflaw parkers, they say. And day after day, they say, they take abuse from angry drivers.

“They’re there in your face just yelling at you, and sometimes your temper does get a little high, [but often] you stay calm,” said Fred Scheler, the owner of Falls Church-based Henry’s Wrecker Service.

Scheler said that his workers treat drivers with respect and that fees are sometimes dropped for drivers who privately plead their cases to the company. He also said towing can make a positive difference for businesses. One restaurant in Arlington County, he said, tripled its business on weekends because of his company’s towing.

Sometimes drivers don’t know the parking rules, Scheler said, and the signs don’t help. They contain too many words in print that is too small. “How do you have the time to read it as you’re pulling off a major road?” he said.

But some drivers take a chance and park where they know they shouldn’t. People think they can get away with it, he said, and when they get caught, they get mad.

In his Rockville office, Doug Numbers, a Montgomery consumer affairs official, fields a towing complaint nearly every workday. He travels to parking lots throughout the county to inspect signs. He serves as a mediator between drivers, angry that their vehicles have been towed, and the towing crew, angry that a complaint has been filed.

Numbers has complaints from all over the county: an IHOP in Wheaton, an apartment complex in Gaithersburg, a Baptist church in Silver Spring.

For years, Bethesda has had towing problems, and the situation has been exacerbated in recent months by construction on two corners at Woodmont and Bethesda avenues. The work closed two parking lots having a total of nearly 300 metered spaces. Recently, Wheaton has become a hot spot for towing complaints, officials said.

The complaints have come from drivers who were trying to buy groceries or a morning cup of coffee. Crews have taken vehicles that held medication, cellphones and laptops. Sometimes, yes, the drivers did leave the property for an errand, but they also shopped where they were supposed to shop. And really, they say, shouldn’t that give them a little leeway?

Businesses complain about towing, too. “Some people park here for 10 minutes and then get their car towed,” said Gladys Pastram, a supervisor at a Wheaton beauty salon. “That’s not right.”

In December 2010, Funmi Elemoso parked her blue Geo Metro at an Exxon station in Wheaton and left the premises to find a teller machine for gas money. She said a tower quickly swooped in and said he wouldn’t return her car unless she gave him $150. Her brother, who was with her, told the county’s consumer protection office that he threatened to call police, and the tower drove away with the car.