While HTC has announced that they will unlock their bootloaders, it's unclear what "unlock" refers to. I suspect they will remove the encrypted signature (which is really what people were protesting, btw, whether they knew it or not). But NAND protection will still be on at the time of activation. It's up to the user to then find the means to unlock the bootloader. Business as usual.
I doubt HTC would have made this very public announcement about unlocking the bootloader if the carriers would never agree to it. Because the end user doesn't know/care who is enforcing the lock. If the end result is not an unlocked bootloader, HTC will take the hit. Which is why I think either the carriers don't care, or they don't have the leverage to prevent HTC's decision.
It's also likely that the decision to lock the bootloader never had anything to do with the carriers.
I'd love to see Motorola follow suit and announce a change in their bootloader policy. Sony, Samsung, and now HTC are moving toward lax bootloader security. So Moto is really starting to stick out like a sore thumb.
If you're interested in learning more about what all the hoopla is about, take a look here for some basic definitions of locked, signed, and encrypted, as they relate to the bootloader. It was written for an HTC audience, but it's still very applicable to Moto.
http://androidforums.com/evo-3d-all-things-root/342046-encrypted-bootloader-properly-defined.html