Dear Miss Manners: I recognize that the general rule is that it is polite to pay attention to those people actually in one's presence and not chat on a mobile phone when you have live people right there with you.
But what about the instance when you are intentionally off alone, on the phone, and others come up to you and interrupt the conversation?
I am thinking of a situation in which I was waiting for my significant other to fill out some forms at his new job. We had driven together because we had some mutual errands to run after he finished. I happily spread out on a blanket under a tree, rather far from the office building, got out a snack for myself, and, once done eating, called my brother on my cellphone to inquire as to the health of my sister-in-law, who was quite ill.
We were discussing whether I should come visit, when all of a sudden, I barely heard my name being called from afar. It was my significant other and his new boss, waving at me and calling out; apparently, she expected to meet me! So of course, I got up from my blanket, crossed the field to the building and shook hands with her, telling my brother to hold on a minute and apologizing to her for being on the phone.
But I wondered ever since what the proper protocol was. Is there a polite way to say, "I'm sorry, but I'm on the phone just now" (which obviously can't be done with a boss)? Or is it always rude to ignore those right in front of you, even if they have interrupted you when you were quite obviously trying to have a conversation in private?
So many people are, understandably, irked at being ignored in favor of a companion’s telephone that Miss Manners welcomes a reminder that the underlying etiquette is more concerned with seniority than technology.
Your brother comes first, not because he is family, but because the conversation with him preceded that with your partner and his boss. And this would be true whether the interruption was from your spouse’s new boss, or his old barber.
In either case, it is important to convey to the interloper that he is intruding — while acting as if the rudeness was unintentional. If in proximity, the correct response is, “I’m sorry, but I was just in the middle of a call,” but mouthed, so as to be only barely audible, and accompanied by your free hand pointing at the phone.
The theatrical delivery is meant to dramatize for the newcomer that this is an interruption not only of the call, but of an actual person. In your case, the same delivery could have been used, albeit less effectively, once you had closed the distance — although you could have also used the travel time to tell your brother you would call him back.