The carrier I'm talking about is a smaller one from Europe. It's unthinkable to ask this of Vodafone or Orange (the 2 big ones) since their heads are really up their buts. And the unlocking prices they charge are freakin` insane! It's not as if carriers can't do this, they just don't want to.
I really don't understand what's their problem. If I'm terminating my contract I have to pay the phone's subsidized price for the months remaining, their only loss is me as their customer, so WTF is the deal with sim-locked phones? I hate it when companies, instead of pleasing customers, are innovating in better lock-in methods.
But yes, I was talking about bootloader-unlock in my previous message. Really, Nexus S is the best Android sold right now, unfortunately it was only available from Vodafone and I'll never make a contract with Vodafone again.