Originally Posted by Hadron
International handsets, no problem. Don't yet know about S-Off.
The existence of the Developer One does suggest that at least some US carrier-supplied sets might be harder - otherwise why bother if you can just go to HTCDev and unlock it anyway, unless it's a publicity stunt? That's just an inference on my part though, not knowledge. Hopefully we'll know soon.
When the One XL hit on ATT in the US last year, they had HTC restrict that device from being able to use HTCdev to unlock at first.
No idea, this could be a publicity thing, but never put any level of shenanigans past any American cell carrier.