I am in a cover band Friday we tune up open with American Girl, I come in and somethings messed up. I have to play 1/2 step higher screws up all my open string stuff and distracts me from my back ups. After the song my guitarist says retune, I said I am in tune, maybe you left your guitar in standard ( we normally play 1/2 step down) he checks his guitar and start the next song and of course I am still flat 1/2 step. Play the whole 1st set play 1/2 step up. In between sets I figured out what happened. I run sound and lights also, so it made for an interesting 1st set.