Coughing is not always involuntary. You hear incessant coughing and hacking in concert halls all the time, even in the most intimate passages, and it seems to be growing. My theory is that it is a way to inject oneself into the performance, for whatever psychological reasons. As someone with aspy tendencies, I prefer to stay home and listen to recordings, rather than raise my blood pressure dealing with the tasteless cretins who pass for polite society today.