If you purchased the phone unlocked direct from Apple and the Activation Process ends up locking it to the carrier, you can always call the carrier and demand they return it to the unlocked state since it is not a subsidized phone. After all, You paid full price for it. It's yours.
Also, thanks to recent Government intervention on subsidized phones - once your contract has come to an end (IE: your 3 years are up) you can phone your carrier and demand they unlock your phone since you have fulfilled your terms of the subsidy. I would imagine even if you cancel your contract and thus pay your early cancellation fee (which covers the balance of the subsidy), you can have the carrier unlock the phone so you can take it to another carrier.
Also, thanks to recent Government intervention on subsidized phones - once your contract has come to an end (IE: your 3 years are up) you can phone your carrier and demand they unlock your phone since you have fulfilled your terms of the subsidy. I would imagine even if you cancel your contract and thus pay your early cancellation fee (which covers the balance of the subsidy), you can have the carrier unlock the phone so you can take it to another carrier.
