I asked the same question elsewhere, and someone came up with this hypothesis: http://forums.macrumors.com/showthread.php?p=16266984#post16266984 http://forums.

I asked the same question elsewhere, and someone came up with this hypothesis: http://forums.macrumors.com/showthread.php?p=16266984#post16266984 http://forums.macrumors.com/showthread.php?p=16266984#post16... ...I still think APN blocking is entirely irrational on the part of the carrier. There's no way a user can subject their carrier's network to fraud or abuse by having access to the APNs (http://forums.macrumors.com/showthread.php?p=16266682#post16266682 http://forums.macrumors.com/showthread.php?p=16266682#post16...)