A few years ago at a concert at Meany Hall in Seattle, an audience member sitting at the front of the house had a coughing fit, and pianist András Schiff walked off the stage.
Well, it's still pretty annoying, although there are a few things you can do to minimize the distraction to those around you (cough drops, covering your mouth, leaving the auditorium for violent spells, or just simply staying home if you are sick) but coughing is often very hard to control. The distraction from the damn phones and PDA's is completely avoidable if the owner has an iota of consideration for fellow audience members.
Unfortunately sometimes coughing seems to be contagious though and sets off a chain reaction like one dog barking and then all the other neighborhood dogs start barking in response.
Going back to that age-old, rather than techno-hot, distraction of coughing in a theater and performers response, my favorite story is tenor Jon Vickers' reaction.
Vickers is a pretty prickly sort anyway but he had had enough of the audience provided obbligato to his singing during a performance of Tristan und Isolde in Dallas many years ago. During Tristan's long scenes of delirium in Act 3 Vickers snapped. He stopped singing and yelled out to the audience "Shut up your damn coughing". A resourceful amateur documenter (read bootlegger) captured the performance, with Vickers' outburst, on tape.
Jon, let us know how you REALLY feel......