Around 2001 there were all kinds of laptop battery recalls, where they would send you two new ones and a box to return the old one; that's above and beyond. Since battery replacement is not applicable and advance shipping a $$$ phone return is a big risk, Samsung could have worked with carriers to authorize replacement of carrier branded models at the carrier store, even if original purchased somewhere else. If the phones are serviceable, they could have made a replace the battery while you wait program, so people don't need to transfer data etc.