The attenuation or antenna signal-loss issue that was said to affect the iPhone 4 upon its US AT&T release was not as bad globally as earlier reported and as a result, Apple will end the iPhone 4 free-case program on September 30. This case replacement program was estimated to cost at the time it was announced Apple $175 Million.
Apple's statement on the matter.
"We now know that the iPhone 4 antenna attenuation issue is even smaller than we originally thought. A small percentage of iPhone 4 users need a case, and we want to continue providing them a Bumper case for free. For everyone else, we are discontinuing the free case program on all iPhone 4s sold after September 30, 2010. We are also returning to our normal returns policy for all iPhone 4s sold after September 30. Users experiencing antenna issues should call AppleCare to request a free Bumper case."