The exchange was tense between the customer and Jesse, a Trader Joe’s employee sporting a white face mask and a flowery Hawaiian shirt.
“Why aren’t you wearing the mask?” Jesse asked the customer on a recent day at a store in Rancho Palos Verdes, Calif. “I am not here to question what you believe in. These are the rules. I am just asking you kindly to wear the mask.”
The customer, Genevieve Powers, who was recording the entire exchange, refused. “We are in America here,” she said, “Land of the free.” Then she turned her camera on other shoppers, who were less than amused: “Look at all of these sheep that are here, all wearing this mask that is actually dangerous for them.”
Jesse, identified only by his first name in the video, telephoned the police, who did not arrive. Finally, when Ms. Powers left the store, others customers burst into applause.
As more parts of the country reopen businesses, many retail workers have reluctantly turned into de facto enforcers of public health guidelines, confronting customers who refuse to wear masks or to maintain a wide distance from others. The risk of a violent reaction now hangs over jobs already fraught with health perils.
A cashier told a man refusing to wear a mask that he could not buy a pack of cigars at a convenience store in Perkasie, Pa. He punched her three times in the face.
And in a confrontation that turned deadly, the security guard at a Family Dollar store in Flint, Mich., was shot and killed after insisting that a customer put on a mask.
Meegan Holland, the spokeswoman for the Michigan Retailers Association, said stores were caught in the middle. “People can get belligerent when being asked to do something that they do not want to do,” she said.
Masks have been recommended by public health officials as a key way to diminish the spread of the coronavirus, with at least a dozen states requiring them and many others issuing a hodgepodge of county or municipal orders.
They have also turned into a flash point in the country’s culture wars, with some defending their right to not wear one.
“We have individual rights, we don’t have community rights,” said Ms. Powers, 56, the customer at the Trader Joe’s store, in an interview this week.
Public health experts said this argument was misguided.
“I never had a right to do something that could injure the health of my neighbors,” said Wendy E. Parmet, the director of the Center for Health Policy and Law at Northeastern University.
Mask opponents generally overlook the fact that such regulations are meant to protect other people, not the person wearing the mask, she added.
Americans are navigating a patchwork of conflicting national and local guidance on masks. The Centers for Disease Control and Prevention, for example, initially downplayed the efficacy of masks but now recommends them.
And they have become a ready symbol for those dubious about giving government officials wide powers for an extended period.
Retailers find the confrontations over masks a minefield.
“It is a very hot button issue,” said Kenya Friend-Daniel, a spokeswoman for Trader Joe’s. The company declined to allow Jesse, the employee involved in the confrontation, to be interviewed.
“We do not want to put our crew members in the position to have to enforce something like that,” she said, noting that customers “overwhelmingly” wear masks.
In all its 505 stores, Trader Joe’s has put up signs recommending that customers wear masks, not least to protect its employees, Ms. Friend-Daniel said.
Refusing is not grounds alone for being ejected from a store, she said, even where wearing masks in public is the law, but creating a disturbance that bothers other customers is.
Target, in places where masks are the law, has stationed security employees outside its stores to remind customers to wear them, said Jake Anderson, a spokesman.
Stores are not the only businesses involved. Uber announced that starting Monday, drivers and riders must wear masks, and those who refuse can be kicked off the platform.
Smaller retailers feel especially vulnerable to balancing the need for safety and the need to revive their bottom line.
In Charleston, S.C., at M. Dumas & Sons, a 103-year-old men’s clothing store, employees wear masks in line with a city requirement while customers are offered them at the front door.
Gary Flynn, the owner, estimated that 50 percent of his customers would walk away if required to wear a mask.
“I want whatever I can get right now,” he said, with business inching up but still only 25 percent of what it was a year ago.
He acknowledged that his workers were putting themselves in harm’s way to generate sales. “So it’s a slippery slope and it’s a moral challenge every day to try to figure out what’s the right thing to do,” he said.
Farther up King Street, Las Olas Swimwear boutique was doing brisk business in bathing suits for beach-starved customers, as well as face masks. The store has sold more than 500 masks produced by a New York swimwear supplier.
Daniel James, the owner, stated unequivocally that he would fire any employee not wearing a face mask, but said masks were voluntary for customers.
In Michigan, Gov. Gretchen Whitmer made masks mandatory in late April and allowed stores to bar customers who refused. But she did not criminalize such refusals, so police have only intervened when confrontations turned violent.
In Illinois, Rob Karr, the president of the Illinois Retail Merchants Association, compiled a list of episodes that took place in the first 48 hours after masks became mandatory on May 1.
One customer threatened to get a gun from his car to shoot the worker insisting that he wear a mask. Several employees were hit, while others were verbally abused. Sometimes customers fought each other. The list has only grown longer.
Some police departments refused to respond when stores asked for help, Mr. Karr said, while various retailers were fined $750 for not enforcing the ban.
In Warwick, R.I., a police union initially announced on its Facebook page that it would not enforce Gov. Gina Raimondo’s mandatory mask order, calling it “overreaching” and bound to destroy the bridge of trust built with the community. The police chief then issued a statement saying the department would act.
Lawrence O. Gostin, the Georgetown University professor who wrote the draft public health law adopted by many states, suggested that in the absence of national guidelines, retailers should develop one policy for all their stores and stick with it, whether it has the backing of state law or not — that way the rules would be clear for all customers.
Some experts also suggested it was overkill to involve police in the general enforcement of public health measures.
The issue should be treated like wearing seatbelts or not smoking in public, which eventually became habits, Ms. Parmet suggested, but such consensus must develop much more quickly given the danger from Covid-19.
In Hawaii, that consensus is emerging because neighbors are confronting anti-maskers themselves, said Tina Yamaki, president of the Retail Merchants of Hawaii.
“It is the other customers in the stores that are shaming them to put it back on or commenting,” she said.
Ms. Yamaki compared the mask dilemma to trying to ensure that a young child keeps wearing a hat — one minute it is on, and the next minute, after you look away, it disappears.
“We cannot be policing that all the time,” she said of the masks. “We are not that type of law enforcement.”
Christopher Dixon contributed reporting from Charleston, S.C.