There are two unlocks. one for the carrier, one for the bootloader. Until the bootloader is unlocked by the vendor or carrier, it has to be hacked for root and ROM to be installed. Motorola is probably the most willing to offer bootloader unlocks for their devices, but the carrier usually has final say for official unlocks.
The carrier unlock is currently at the carrier's will because the Library of Congress determined it's a copyright violation for users do on their own. Not that this really stops people intent on it. Generally, a carrier is willing to unlock the phone if you pay off the contract on it. or buy it outright.
Unlocking the Bootloader will probably be achieved within the first two weeks of the Not3 general release. Root will quickly follow, ROMs a little later.