Some iPhone users have been experiencing strange problems with their iPhone receiving AIM messages which were not sent to them, but Apple’s push notification system sent it to the wrong people. However it’s not Apple’s fault as some believed it to be.
The iPhone generates unique private/public keys upon activation that identity each handset, so that they correct messages can be sent to the correct device. However using unlocking tools breaks this as they use duplicated keys to facilitate illicit use. Now that single identifiers have been registered to multiple phones instant messages, messages can be sent to any of those devices.