Correction, some kid at the 'Genius Bar' confirmed it.
What you describe is exactly what I've experienced on more than one iPhone when the battery failed... but yeah, good luck convincing them to swap it out under warranty if they're certain that's not the problem.
What you describe is exactly what I've experienced on more than one iPhone when the battery failed... but yeah, good luck convincing them to swap it out under warranty if they're certain that's not the problem.