iPhone loses account info

[FredZ]

I've seen this twice in the past week: I power off my iPhone and go to bed. In the morning, when I power it back on, it seems like it has lost my account information. It shows a picture of the usb cable with an arrow pointing up to an iTunes icon. The ATT service in the corner does not show up. If I slide to unlock it brings up an "emergency" phone keypad. When I plug in the usb cable, iTunes starts up and connects to the iphone. At this point my iphone is back to normal. What is going on here? What happens if I am away from my computer with the iTunes account when this happens: how would I get my iPhone to work?

 

[Voltaic Shock]

Mine has done this before. I just turned it off and back on then it worked. It is really annoying when this happens though. This is why they need a way to activate your phone without iTunes. I'm fine with it having to have been activated at least once with iTunes, but everything after that I should be able to do.