I wasn't sure whether to put this under Army or Your Redneck Past. 

The audience helped him get through the lyrics of the latter number, just as they sang the horn parts and harmonies of Folds' own songs "My Redneck Past" and "Not the Same." Nearly as much credit goes to them as to Folds for making the show a memorable one.
– St. Louis Today

The audience singing horn parts? That has to be Army.  Ben hasn't played Your Redneck Past solo.  It's easy to see where the confusion comes in... Army's lyric "My redneck past is nipping at my heels." Followed by "Your Redneck Past" on the album.  Explainable... but still funny.