"They should always be off and out of sight during meals, meetings and parties," insists Diana Mather, of The English Manner consultancy. "The person you're with is the person who's the most important. None of us is indispensable."
But even looking at the screen at the dinner table is not on - for some. More than four in five people aged 55 and over think it's unacceptable to check notifications, compared with around half (46%) of 18 to 34-year-olds.
They've got their head down, eyes peeled to the screen - and they're right in your path. Internally you're screaming Look up! Look up! But no - it's the pavement slalom again - dodging in and out of pedestrians in the phone zone.