Couple of random thoughts while watching the video . .  
&gt; Agree with Mark's idea,  it seems like they learned the song for a specific purpose - i.e. backing for that montage of a lot of people "singing" the song.  If that is the case,  then wouldn't it need to be the version people are so very familiar with . . or maybe W.T. even requested it that way? 
&gt; If the song stays in the regular setlist mix,  it more than likely will develop its GPN signature.  
Guess we'll have to wait and see what happens. :)