A Canwest News Service story recaps "Music's top 10 most shocking stage performances of 2009," many of which involve the "shocking" spectacle of a performer battling gravity ("Steven Tyler falls off stage," "Leonard Cohen collapses in Spain"). Coming in at Number 3 we have: "Joaquin Phoenix wails on fan at rap show," a tawdry recounting of an alleged assault on an alleged heckler during an alleged show by the alleged singer.
The problem is that to beat on someone is to "whale" on them. Unless they were talking about his singing, in which case it was all the fans who were "wailed" on.