Ashlee's Band is the Lone Gunman.
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Seriously: What? Have you ever ever seen a musical act go on stage and perform the wrong song? If you have, haven't they immediately stopped, been all like "Oh yeah, sorry Mr. Clapton" and then started the correct song? The only times I can remember performers fleeing the stage were Ashlee Simpson on SNL and Milli Vanilli at the MTV music video awards.
Coincidence?
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