(CBS Local) — “No mask, No service” signs are popping up at all kinds of businesses as the country begins to slowly reopen after the coronavirus pandemic shutdown that began in March.

Some retail chains, like Costco Wholesale, have already started to require masks for all customers and employees.

The move follows a flood of videos on social media showing shoppers who refuse to wear face masks being confronted by store employees (and other shoppers, in some cases) who explain that customers are required to wear masks.

But can store owners legally enforce that policy? The short answer is yes, as long as they don’t discriminate against anyone on the basis of “protected classes” such as gender, race, age, disability, national origin and religion.

“All businesses have the right to refuse service so long as it is not violating one of those protected classes,” Robert Mascari, chief assistant district attorney in Madison County, New York, told Syracuse.com. “You can’t refuse to serve me because I’m half Italian and half Irish. You can refuse to serve me if I’m being an idiot.”

Constitutional law and First Amendment rights lawyers say face masks requirements are similar to “no shirt, no shoes, no service” policies or when businesses have a cash-only policy or make sales final.

If you don’t agree with a requirement or a rule that a private business has, they say the only right you have is to make the decision not to shop there.

If a customer gets angry and refuses to put on a mask, the retailer should try to avoid a confrontation and call the police instead, Ted Potrikus, executive director of the Retail Council of New York State, said.