TUAW says : Apple Geniuses are reportedly unbricking iPhones
"Apple continues posting warning signs around their stores, cautioning customers that unlocked and modded iPhones fall outside their warranty. And at the same time, Apple Geniuses around the country quietly are reportedly accepting bricked iphones, slipping into the back and returning with functioning units.
We're not sure whether they're doing a low-level reflash or just swapping units out. We have reports of at least four customers who walked in with iBricks and walked out with iPhones. It is unclear at this time whether these customers unlocked their iPhones or not--we're also receiving reports of iBricks from people who never unlocked or modded their units."
So apple caused a problem, to force a relock on you!