It’s often the subtle but creepy stuff: a lingering stare, an intrusive question, even an unwanted touch on the arm. Women get that every day on the street, and the servers at Homeroom, a busy mac-and-cheese restaurant in Oakland, were tired of getting it from their customers, too.

“It’s when people start asking personal questions. ‘Where do you live? What are you doing later?’” says Kayla Sorensen, 30, a Homeroom manager and former server. “They’re trying to get (servers) to break character out of service and into this personal connection. That’s where it flips for some people.”

After a particularly upsetting incident three years ago, the Homeroom staff got together to brainstorm solutions. They came up with a color-coded system that allows a server to tell her manager if a table is behaving badly simply by saying yellow, orange or red to indicate the level of harassment. The manager then handles it accordingly: In some cases by taking over the table. In rare instances the customer gets the boot. Managers and staff say the system has virtually eliminated serious issues with harassment.

If widespread harassment seems surprising at a casual place where about a third of the tables are filled with young families on a Wednesday evening, it’s only an example of how endemic the problem is. Seventy-eight percent of U.S. restaurant workers report sexual harassment from customers according to a 2014 Restaurant Opportunities Center United report.

At the same time, younger people are showing less tolerance for harassment. A recent Economist/YouGov report found that over a third of Americans ages 18 to 30 consider comments on a person’s attractiveness to be a form of harassment, while a quarter of men and about 20 percent of women in the same age group say the same thing about being asked out for a drink.

Homeroom’s system allows the server to define harassment herself. The restaurant’s founder and CEO, Erin Wade, is a former labor and employment lawyer. She says that dealing with smaller, insidious forms of aggression prevents worse behavior from following.

“Actually trusting women’s instincts and their discomfort — frankly, what they’re used to facing out in the world — keeps it from escalating,” says Wade, 36. “When a man is starting to use suggestive behavior toward a woman — looking her up and down or making comments on her appearance — it’s a way of asserting power. When all of a sudden that woman disappears and a manager steps in, it changes the power dynamic.”

At Homeroom, new employees are trained on the color-coded system — which they call Management Alert Color System or MACS (get it?) — when they’re hired. It applies to customers as well as vendors, such as the couriers who work for online delivery services such as DoorDash and Caviar who come through Homeroom’s to-go location a block from the restaurant.

Yellow: Someone gives you a creepy vibe or even just a leering look. Orange: A person makes a comment with sexual overtones or an unwelcome compliment. Red: An overtly sexual comment or touch, or repeated “orange” behavior after the person has been asked to stop.

In the restaurant, if a server experiences a “yellow,” the most common situation, the server can ask the manager to take over the table or just to keep an eye on it. Orange requires the manager to automatically take over the table. Red means the customer has to leave.

Though “red” situations are rare, Homeroom waitress Chrissel Orcino, 28, did have one such incident this summer. A man sitting at a booth with another man and a woman was so intent on picking up the tab that he interrupted Orcino while she was talking and slipped his credit card into her middle apron pocket.

“I could feel his hand going really far down my waitress apron. I could feel his knuckles right above my crotch,” she said.

Orcino abruptly told him he could have used “words” then left the table to inform her manager, who immediately closed out the table’s tab. The man then followed Orcino around the restaurant trying to hand her the signed check, she says, until the manager intervened again and the man left.

“That was really horrible,” Orcino says. However, for her, the restaurant’s system worked really well overall. “All I had to do was exchange a few words with my manager and that’s all it took to take action.”

As a former labor and employment attorney, Wade was particularly sensitive to preventing harassment when she opened Homeroom in 2011, which she calls a feminist restaurant company. She made sure to train staff on sexual harassment every two years — as required by state law for businesses with more than 50 employees — and promoted female managers from within. Her company now has close to 100 employees; 70 percent of the management team is made up of women and people of color.

The incident that spawned the system happened in late 2014. The staff was in an uproar after a busser said a customer slipped his hand under her shirt and stroked her bare belly right when she was serving his family.

The waiters said they didn’t know what to do when similar things had happened to them. When they reported uncomfortable situations to their floor managers, who were mostly men at the time, the managers didn’t really get it.

“There would be times when a customer said something that was borderline inappropriate. Maybe I didn’t take it as seriously as I do now,” says restaurant manager Kale Irwin, 33. “Before we really started this conversation, I wasn’t as tuned in to it.”

Irwin says that now he never thinks employees are being too sensitive when they use the color system to report issues with customers or vendors.

“It’s pretty clear where somebody’s coming from when they do make those comments,” he said. “I still think it’s a violation of somebody’s personal space.”

Another reason the restaurant managers say they want to deal with these kinds of problems right away is to make sure the workers can do their jobs properly and serve their other customers without distraction.

“We’re generally about empowering staff to make decisions,” says Haiden Tullis, 24, who is in charge of staff training. “At other places you may have been told to be quiet about this. But we want you to speak up because it not only helps you, it potentially helps others.

“It’s really courageous when people do say something,” Tullis says.