I actually am not jailbroken. I have been having some issues with my iPhone 4 connecting to wireless networks and sometimes having four bars of service and no data, while my 3GS works fine.
I had my 3GS replaced before, and when I tried to replace my wife's iPod Touch for the same problem (battery not lasting as long as it should), they wouldn't because I hadn't restored it.
I don't want to restore my iPhone 4, because in all their infinite wisdom, Apple's system is SEVERELY flawed as there is no way to back up your app data in this sort of situation, and you will lose everything if you do a complete restore. I was hoping to be able to restore from backup so I could say that I had, and then they would replace my phone. Then I could come home, restore from backup, and still have all my current data on my new phone.
A complete restore is a MAJOR pain when you use your phone for business, and have tons of information saved on it. Until Apple can allow you to back up your app data separately, they will never be a true competitor in the enterprise or games markets.
Anyway, that's why I was asking. The nearest Apple store is two and a half hours away for me, so I really don't want to make the trip to find out they're going to shoot me down because I hadn't restored.