It is important to remain "present" as a leader. That doesn't mean simply "being there" for your staff. Successful leaders take advantage of "leadership moments" to provide examples to others.
With several articles now openly discussing Apple's PR problem, the world is becoming increasingly aware of worker conditions at Foxconn, one of the major manufacturers of Apple's devices. One example:
[The New York Times] detailed allegations that workers at Foxconn suffered in conditions that resembled a modern version of bonded labour, working obscenely long shifts in unhealthy conditions with few of the labour rights that workers in the west would take for granted. It also mentioned disturbing events elsewhere in China among supplier firms, such as explosions at iPad factories that killed a total of four people and another incident in which 137 workers were injured after cleaning iPhone screens with a poisonous chemical.
Right now, Apple is in the spotlight. And Tim Cook, as the new CEO, is experiencing his leadership moment. Leaders need to have positive presence, to be able to bring some energy into the room and energize others. What he does in the next few days or weeks will demonstrate his leadership presence, and define his legacy at Apple.