The menu lock/unlock is controlled by whichever included carrier profile your SIM card IIN is associated with. My Straight Talk SIM card has an AT&T IIN, so it automatically uses the AT&T carrier profile (to my great annoyance, as if that weren't already clear to everybody :-)). A carrier might decide to not lock the menu for their customers, and if you have a SIM card that has no associated carrier profile, you will automaticall be granted open access to the menu.