"I think some employers are afraid of alienating customers. They don't want to lose business. And so they don't enforce [face-covering regulations]. I also think some employers know that, unfortunately, wearing a mask has become politicized and they want to stay out of that debate. It's wrong. They need to enforce the rules."

Stuart Appelbaum, president of the Retail, Wholesale and Department Store Union, in a recent interview with NBC News.