Overcaptioning: Which sounds are significant?

Which sounds are significant? How does the captioner choose which sounds to caption? Are some captions unnecessary? Why isn’t it possible to caption every sound in the environment?

The PA announcement at the end of Taken

Consider the emotional family reunion at the end of Taken, a 2008 thriller starring Liam Neeson. The reunion at the airport following the rescue of Neeson’s daughter from human sex trafficking is disrupted by a captioned, incomplete, and ironic announcement over the airport’s public address system. As the family embraces and speaks to each other in person for the first time since their daughter was kidnapped and sold into sex slavery, a partially muffled PA announcement interjects on the caption layer. A question from the stepfather (“Shall we go?”) interrupts the PA announcement just as the announcer is about to tell viewers and listeners what is “not required.” The main point of the announcement is muffled as the stepfather speaks. It is not possible for hearing viewers to make out the uncaptioned spoken words of the PA. Ironically, the movie itself is about activities that are not officially “sponsored” (i.e., kidnapping, human trafficking). In this sense, then, the PA announcement is relevant to the larger themes of the movie, even if the announcement is most likely not a public warning about kidnapping or slavery. But irony should never be enough to trump a scene’s thematic intensity. Because the announcement disrupts the emotional intensity of the triumphant reunion, and its main idea is inaudible (whose activities are not sponsored?), it should not have been captioned verbatim. A complete, verbatim rendering of the announcement is impossible anyway and only leads to confusion and distraction.