On iOS 6 at least

The annoying bug that plagued all iOS devices has been successfully resolved in iOS 6

Do you remember that horrible bug consisting in stolen iPhones still receiving texts even if they were remotely wiped? That allowed thieves to read your private messages no matter what you do. Well, we are happy to announce that Apple has resolved such issue in iOS 6.

According to TheNextWeb:

According to a source with knowledge of Apple’s steps to correct the matter, the issue has been fixed in iOS 6 through a variety of checks placed on iMessage. The most important of these is that Apple now uses its push systems to force a user to re-enter a password to use iMessage once your Apple ID credentials have been changed.
NEWS SOURCE: Bug that allowed stolen iPhones to continue receiving iMessages has been fixed in iOS 6 (via) TheNextWeb

Our thanks to 'Kaos2K' for this news item!