Roger Waters also use backing tracks in his shows, even for his vocals and bass parts, I remember a concert in Barcelona that I was close to the stage I listen to Roger´s voice and he wasn't at the mic, he hurried to the mic when he realised... and in other parts of the show you could listen some bass lines and Roger neither his other bass player were playing. After that I decided to not go to his next concerts. I totally understand you use backing tracks for effects, programings etc, but the main things in the songs, no, thank you.