The old rule of presenting yourself in public used to be: Maintain eye contact. Not doing that could dim your wattage as a keynote speaker or panelist or knock you out of the box for a job or client assignment. The new rule of presenting yourself in public, which those of us in speechwriting hammer, is: No checking your smartphone.
Admittedly, it's tough not to take a smartphone peek. And it's not a stretch to say we're "addicted" to our smartphones. All that is the case. But checking it, even by important politicos, short-circuits the electric current between presenters and audience. Yes, members of the audience are insulted.
Those who coach speakers as well as job applicants and salespeople must make the warning explicit: Never never never check your smartphone. Not while you're waiting to present. Not during it. And not before you leave.