If people are treating the singing as wallpaper they will be unlikely to notice any irony or subtlety. Unfortunately there are also occasions when it's not the amount of beer of background noise that hinders people's understanding but almost a type of mental laziness. It's as if they are used to everything being made so obvious only those with a mental disability could fail to understand. This seems to be true in lots of other areas as well. It was once expected that people would have basic common sense, now it seems more and more often the population is treated as if stupidity and ignorance is seen as the norm.   

But getting this thread back to the music another ironic song I love is Micca's "My grandfather hated the Germans".