Originally Posted by Concordia
12 years ago in HK, I was amused to sit in a decent-ish restaurant for lunch and watch teenage couples on dates carefully place glitzy his'n'hers cellphones on the table next to their cutlery. The more advanced might refer to that gesture as a tribal marking, perhaps.
On a related note, there is an interesting article by some economists in Liverpool (if memory serves) explaining how men and women use their cell phones differently in public and concluded that the phone was used as a lekking device by the men. That is, like peacock feathers, the males used them as a means of attracting the opposite sex by showing off their importance (constant need to check for messages) or wealth (fancy phone).
They likened this, amusingly, to teenage girls who used their cellphones (and the phonebooks in them) to develop social status by showing how popular they are.
So perhaps these people we see at dinner tables using their cellphones are, in their minds at least, not being rude, but are trying to attract a mate or build their social network. Of course, the rest of us can still think it's rude.