being the iPhone n00b that i am, i'm feeling uneasy about JB-ing my 3GS (when the time comes). i've messed with hacks for BB and other phones, but just not as experienced with Apple products. don't want to ruin a perfectly good device.
am i correct in thinking that i read somewhere, if you restore through iTunes, the iPhone will go back to ground zero? so that if i had to return to Apple store for repair, etc., they wouldn't know i JB'd my iPhone and voided the warranty?