The gala is not over until the Fat Pig sings!  The Fat Pig will sing when she hears "Kaching".

Traditionally the fat lady refers to the opera diva, who often large, would end the production with an aria or solo.

Regarding Pork Fat.  Patty needs to maintain her healthy weight in order to maintain her healthy vocal chords.  Put a healthy chunk of change into Patty and she will sing specifically to you for Flagstaff!