Walmart and other major retailers made headlines last week with a new requirement for customers to wear masks in its US stores. But the new rules only go so far. Walmart\n \n (WMT), Home Depot\n \n (HD), Lowe’s\n \n (LOW), Walgreens\n \n (WBA), CVS\n \n (CVS) and others say they still won’t prohibit customers who refuse to wear a mask from shopping in stores. The issue, they say, is they want to avoid confrontations between angry customers and employees. Retailers and their employees are finding themselves playing the uncomfortable role of mask police. The increase in coronavirus cases is prompting concern over how to protect both customers and workers in crowded stores from infecting each other. There is no federal mandate to wear a mask, and many state and local governments have not required wearing one. This has forced retailers to navigate a patchwork system and left them in the position of having to create their own policies. “Many retailers feel like they have to act since some governors haven’t,” said Melissa Murdock, spokesperson for the Retail Industry Leaders Association, which represents companies such as Walmart, Target, Walgreens and others. The group wrote to the National Governors Association on July 6, saying that public officials should issue uniform mask mandates across all 50 states. Labor advocates and retailers agree that store employees should not be the ones enforcing mask wearing. But it’s not clear who will fill the void. Critics say that makes the new wave of retailers’ mask requirements toothless. “Either security or management needs to tell people that they must wear a face mask in order to be served. It’s no different than wearing shoes or a shirt,” said Stuart Appelbaum, president of the Retail, Wholesale and Department Store Union. If companies “are not requiring customers to wear a mask within their store, then they never had a requirement. All they had was a public relations stunt.” Violent incidents Anti-maskers have sparked violent incidents at stores, restaurants and other businesses over requirements to wear them. A security guard at a Family Dollar store in Michigan was shot and killed in May after he told a customer to wear a mask. In recent weeks, videos of confrontations between angry customers and clerks at Costco\n \n (COST), Target\n \n (TGT) and other stores over these rules have gone viral. Companies want to avoid such incidents. Walmart, the largest retailer in the country, said it would station employees it calls health ambassadors at the entrance of stores to remind shoppers about mask compliance as they enter. But a short training video for health ambassadors makes clear there are limits to the job. If a customer refuses to wear a mask, health ambassadors are instructed to let the customer into the store and notify management “so that they can determine the next steps.” In talking points for Walmart ambassadors and management, a member of management is instructed to ask if the customer would like a complimentary mask. If the customer refuses, “let them continue to shop,” the talking points say. The video tells ambassadors never to engage with a customer physically or try to block their entrance into the store. “With every requirement there are exceptions that have been established to avoid escalating the situation and putting our associates in harm’s way,” a Walmart representative said. “Our goal is to keep associates from a physical confrontation in the stores.” Walmart is also adding signs about the policies, which exempt small children and people who can’t wear masks due to health conditions or religious beliefs, and announcing them over store loudspeaker. The home improvement chain Lowe’s says it’s also added signs at its stores, requesting that customers wear masks for the safety of everyone. It is also providing free masks to customers who need them. “We will not ask our associates to put their safety at risk by confronting customers about wearing masks,” a Lowe’s representative said. Indeed, a Home Depot spokesperson compared the company’s mask requirement to its shoplifting policy, where employees are told not to block the entrance or chase after a customer. “It’s too dangerous to forcibly or physically deny entry.” Meanwhile, CVS said it will “ask for [customers’] cooperation” with the mask policy. “In the event of non-compliance [the store] will expedite their transaction and provide them with other options for their future needs,” such as delivery and drive-thru,” a representative for the company said. Retailers internationally are also making similar calculations. Face masks in shops also became mandatory in the United Kingdom Friday. People can be fined £100 ($127.48) for not wearing one, with some exceptions for medical conditions. Leading retailers have said they will encourage customers to wear masks but won’t enforce the law themselves. That means people without masks will still get served. Asda, the British supermarket chain which Walmart put up for sale this week, said it would “strongly encourage” customers to wear a face covering and would have masks available to buy at the front of stores. Luxury London department store Harrods said the government list of exemptions means staff will have to be “mindful and respectful” when asking customers to wear masks. Swedish furniture maker IKEA, which has 22 stores in the UK, said it would proactively encourage wearing masks, but that the government has asked the police to handle enforcement. “While enforcement of this policy will be handled by the police, the ultimate responsibility remains with customers who must ensure that they wear a face covering when going into stores,” said Tom Ironside, director of business and regulation at the British Retail Consortium. ‘Makes complete business sense’ Companies in recent weeks shifted their own policies on masks in response to the coronavirus raging across of the country and record cases in many states across the South and West. “This was the right time to implement the requirement in our stores” to stop the spread of coronavirus and protect workers and customers, the Walmart spokesperson said. “Our requirement is going [to] result in many more people wearing masks than before.” Companies, public health experts and retail consultants say the growing public acceptance of masks helped spur these policy changes. Retailers want to signal to customers that stores are safe to shop at, and requiring masks can help them achieve that, said Chris Walton, former Target executive and now CEO of the retail blog Omni Talk. Leslie Dach, former Walmart executive vice president of corporate affairs and government relations, said Walmart’s “decision makes complete business sense. ” “Customers want to shop at places they feel safe,” he added. “Having customers wear masks protects employees and protects customers.” Chains also made the policy changes after more cities, counties and states required masks in public spaces. Walmart, for example, said that 65% of its more than 5,000 US stores and Sam’s Clubs were in areas where there is a government mandate on face coverings. Target said that figure for its more than 1,800 stores was around 80%. Around 85% of Home Depot stores were under requirements because of state mandates, and the company “wanted to make it consistent across the board,” the Home Depot spokesperson said. Some retailers have increased their hiring of private security guards to help diffuse confrontations over masks. Companies also have varying policies on whether to call the cops. CVS and Home Depot said they would not call the police if a customer did not wear a mask in an area where mask wearing is mandated. However, the Home Depot representative said “if a customer becomes combative or habitually refuses to comply, we’ll take further action to prevent them from entering our stores.” A spokesperson for Walmart said “while we do try to find solutions for customers who are not wearing face coverings, from time to time we do need to call police for assistance in those areas” if customers become belligerent. Meegan Holland, spokesperson for the Michigan Retailers Association, said, “we would love for police to be more a part of the enforcement role, but that hasn’t happened.” —CNN Business’ Eoin McSweeney contributed to this article.