I had tickets to the theatre to see Jude Law. JUDE LAW!!
I did not go, because I was ill. And coughing. And likely to be a distraction to the many other people who had paid money to see Jude Law, and listen to the words he spoke (it was Shakespeare, but I would have done the same if it had been a punk musical, not quite punk musical or any other event where the audience had an expectation of being able to hear).
Likewise, I would not have taken my small child (who as it happens, was bottle fed not that it makes any difference either way), who, despite being quiet 99% of the time, still may choose to cry if she is upset thus distracting other people who wanted to hear the dialogue.
To refer to math's earlier point - no you might not hear a baby over American Idiot, but you may well hear them over Wake Me Up When September Ends or the dialogue, which, regardless of quality, was holding the songs together to form a story.