Asking customers not to openly carry guns in stores was a big step for retailers. But enforcing it may be more difficult.

How can retailers enforce the policy?

State laws governing how and when private businesses can restrict open carry vary. Typically, businesses have the right to decide who is and isn’t allowed on their private property and what rules of behavior people must follow. It’s akin to “no shirt, no shoes, no service.”

If a customer does not abide with a store’s clearly posted rules, or if someone ignores an employee’s instructions to leave, it may be considered trespassing, said Andrew Karwoski, deputy director of state policy for advocacy group Everytown for Gun Safety.

Those are the rules, but asking workers to enforce them may be another matter. Unlike asking a customer to leave the store if they’re not wearing shoes, approaching a customer who is carrying a gun could present safety concerns.

“It’s very confusing for me because I can’t judge someone based on their appearance, if they are a good person or a bad person. So what I do is I move as far away from them as possible, I can at least try and protect myself,” Gabriela Enriquez, a Walmart associate in El Paso, told CNN Business, speaking through a translator. Enriquez works at an El Paso Walmart that is different from the store that was the site of last month’s shooting. She had, however, worked for five years at the store that was attacked.

The new policies only address guns that are openly carried, not guns that are concealed. To regulate concealed carried guns, retailers would have to pay to install metal detectors, which can be an unwelcoming hassle for customers.

“Even if you do have some way of seeing if someone has a concealed gun, what do you do then?” said Christian Connors, CEO of Shooter Detection Systems, a company that sells shooting detection and alert technology. “You’re going to pull someone aside in a busy area and ask them to pull out a weapon in the middle of a crowd and give it to you?”

How are retailers enforcing the policy?

Walmart has said it plans to take a “non-confrontational” approach to enforcing the policy.

A company spokesperson said that means some customers may be allowed to openly carry guns into the stores, such as customers making a quick stop for supplies on a hunting trip, provided they don’t threaten to cause any harm. But if customers or employees feel uncomfortable about someone openly carrying a gun, Walmart managers or a member of the security team may approach that person to remind them of the policy.

When and how to make those enforcement actions will be left largely up to each store, the spokesperson said, though Walmart is rolling out a training program for handling such conversations with customers.

But the result of this policy so far is that some people are still openly carrying guns into Walmart stores, leaving employees feeling vulnerable.

“It’s not actually a policy, it’s more of a suggestion, and it hasn’t helped at all because customers still keep entering the stores with guns,” Enriquez said. “Before the shooting in El Paso, associates like myself didn’t really notice how often customers were coming in with guns but after the shooting, due to how afraid we all have been in the store, it is absolutely more noticeable.”

“I walk into work afraid every single day, as soon as I enter the parking lot,” she said.

A spokesperson for CVS said it is still determining how to enforce the policy and communicate it to employees. The other retailers declined to comment or did not respond to requests for comment.

Does it matter that retailers are just “asking” customers not to carry guns?

In a practical sense, there is little difference between companies saying they will “ask” or “tell” customers not to carry guns — what matters is how they decide to enforce it. By saying they will “ask” customers not to openly carry guns, retailers may be trying to balance appeasing customers who feel uncomfortable shopping for groceries in a place where people openly carry guns, and not alienating their law-abiding, gun-carrying customers.

In a statement released after Walmart announced the changes to its policies, the National Rifle Association suggested some customers who support gun rights may stop shopping there.

“Lines at Walmart will soon be replaced by lines at other retailers who are more supportive of America’s fundamental freedoms,” the NRA said in the statement.

But potentially missing out on slightly less than half of American consumers’ spending dollars is a scary prospect for these big box retailers.