Experts say you should make the request discreetly because shaming the person could put them on the defensive.

If they feel violated by the way you approach them, they are much less likely to make a change, said Jan Kavookjian, a behavioral scientist at Auburn University. She said citing local rules or recommendations from health officials could also help in some cases.

“Someone feels less threatened when you say, ‘Here’s what the experts say’,” Kavookjian said.

Public health experts say masks are key to reducing the spread of COVID-19. But asking a stranger to put one on could still result in a volatile situation, since they may not be easily persuaded.

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Rather than risk a confrontation, experts say it might be best to steer clear of people without masks in public if you can.

And if you’re in a store or restaurant, it’s best to have a manager or someone in charge ask the person, said Diane Gottsman, an etiquette expert. 

If you do find yourself interacting with someone who is not wearing a mask, Gottsman suggests saying something like, “For your safety and mine, I would feel much more comfortable if we were both wearing masks.”