Bon Iver Live at His High School

This is just about the coolest thing I've read in awhile via Stereogum.  Justin Vernon of Bon Iver fame visited his High School and made the band kids feel way cool.  Who's playing that flute on "Lump Sum"?  

From current student Leo Strei:  

"It's just been awesome to have him with us. To have someone of international fame like this with us is fantastic. What is really cool is how straightforward he is with us. He talked to us as musicians and never talked down to us; it was just like we had been friends with him for a long time."