Billy Joel > U2

I heard on the radio that Billy Joel is giving these Town Hall concerts. It's
part song, part question and answers. Somebody asked him about U2. He said he
was at a U2 concert and found out that they have a band underneath the stage
supplementing.
This is the first I'm hearing of this but I wouldn't be surprised if it was
true. I remember seeing BTO back in the 80's. I had this really big telephoto
lens. From where I was sitting, I could see a guitar player hiding behind the
amps playing with the band for the entire concert.
I think if bands were going to do something like this, they should just have
the other musicians on the stage. I think people realize that what you do on
record a lot of times can't be done on stage without other musicians to fill in
the music.