My phone is carrier unlocked. I have TMobile and a Verizon data SIM in it in the US and an Etisilat SIM in it in the UAE. I''m grandfathered on ATT's unlimited international program so it is the exception (not the rule) for me but definitely unlocked. I got the phone unlocked from the Apple store and it isn't ATT subsidized.

ATT still blocked access to that control. Apple gives the carrier a ton of power over the phone.