If you take the transparency argument out of it, however, the act of being with someone – or better yet, a group of people – and on one’s phone is just the modern iteration of a key pleasure of family life: to be among those whom one is sufficiently comfortable with to drift in and out of communication. Like doing homework at the kitchen table, it is the state of doing your own thing while others do theirs around you. The point is, whatever you are doing on your phone, it would be less pleasurable were you to be doing it alone in your room.
Screen addiction alters this, and there are levels of disengagement that can turn a sentient being into a piece of furniture, but the parameters of acceptable phone use should surely widen at this point to permit some middle way between being on one’s phone and considered rude, or turning the device off altogether.
Perhaps social convention needs to change to budget for the opaqueness of our new behaviors while recognizing their connection to behaviors of old. In a few years’ time, we will, perhaps, automatically offer with every swipe a quick subtitle as to what we are doing, like excusing oneself after sneezing, or giving a running commentary of one’s actions to children.