Yeah, this sort of thing really bothers me, too. I think (hope) that this should become less common in the future. It's taking time for cell phone etiquette to develop, but as they become less of a status symbol and a new technology, people should become more conscious of how annoying and asinine they sound when they're broadcasting their personal conversations to a group of strangers.
Letterman asked Zevon if his condition had taught him anything about life and death. ''How much you're supposed to enjoy every sandwich,'' Zevon answered. (From a 2003 NYTimes article on Zevon by Jon Pareles.)