Frankly why do they want to have the phone locked to an operator. all they need to do is bind the use to a contract and that is it!
that is what happens in certain european countries you can get a plan with a phone for free with a contract of 24 months.
the phone they give you is not operator locked. you can put any sim you want.. however the contract deadline is written in stone and if you want to get out of it you need to 'buy it ' it means pay in full the number of months remaining in your contract.