Samsung Galaxy S III bootloader will remain locked, confirms Verizon
A couple of days ago, a Verizon representative hinted that an upcoming Samsung Galaxy S III software update would unlock the smartphone's bootloader, thus allowing power users to tinker with it all they want. Think installing custom firmware and that sort of things. Unfortunately, it looks like that is not going to happen.
After inquiring, Droid-Life got a response from Verizon on the matter. It turns out that a Samsung Galaxy S III software update is indeed being planned, but unlocking the bootloader is not what it is meant to do. Instead, the patch will unlock GSM roaming on the device, which will make it work on cellular networks around the world.
So yeah, if you want to have one of those Android high-ends with an unlocked bootloader, you will have to settle down with warranty-less Developer Edition of the Samsung Galaxy S III. It is expected to be made available for purchase from Samsung's website for a hefty $599.
source: Droid-Life
Things that are NOT allowed: