iMessage gets tricky when you have multiple devices.<p>For example, I went out of the country, but left my iPad at home (which also receives iMessages to my phone #). Because my phone wasn't data roaming, and my iPad was still on the network at home, iMessages <i>were being delivered</i> to the iPad. It basically meant anyone with an iPhone couldn't text me, because the text message fallback wasn't triggering. I had to find wifi with my iPhone to catch up on texts.<p>The "dead battery" auto-responder has the same issue. What if my iPhone battery is dead, but I'm on a Mountain Lion MacBook and getting messages there?