Is the phone on the seatback in an airplane a mobile phone? How is it possible that so much was spent to install those things without somebody suggesting that people wouldn’t feel comfortable using them. When was the last time you saw one in use? When was the last time you saw two people inside a telephone booth? Proximities matter. Being on the phone puts you in a conversational space that creates its own version of shared space, even though the person at the other end of the phone is physically absent. And any situation that creates an eavesdropping situation for others will create enough potential discomfort that most of us will seek out a more private space from which to make our calls.