The iPhone 4 has become widely known for two things at this point: huge sales and reception problems. Regarding the latter, a document of internal procedures for AppleCare is very telling.
Reps are told to say that the reception for the iPhone 4 is the best of any iPhone model and that gripping certain sections affects reception of all mobile phones. For the iPhone 3GS, it is recommended to avoid covering the bottom-right side with your hand, while on the iPhone 4, it is advised to avoid covering the black strip in the lower-left corner of the metal band.
The use of a case or Bumper that is made out of rubber or plastic may improve wireless performance by keeping your hand from directly covering these areas, reads the document. We ARE NOT appeasing customers with free bumpers DON’T promise a free bumper to customers.
Source: Boy Genius Report
