Verizon is forced to not lock the iPhone 5 because of government regulation, agreement that Verizon has to abide to when they got the LTE 700MHz spectrum.
LTE has nothing to do with locking the devices.
Verizon on LTE does lock their devices.
The Razr HD and other LTE devices are locked so you cannot move them to a new domestic carrier. They are internationally unlocked.
But with it being legal to unlock you phone in Mexico and Canada *AND* just about everywhere else in the world, this is unenforceable.
The web levels the playing field.
People will just use a service located outside the US to do this.
Anyway, most carriers unlock your phone if your contract terms have been fulfilled. Once you are off contract, it is your device and the subsidy has been paid.
I now buy more phone retail anyway so I don't lose unlimited.