Let's be clear. If you buy an unlocked iPhone from Apple it is unlocked and never will be locked to any carrier. Apple employees don't get a commission so no need to lock a phone to a carrier to get a commission. However, there are retail stores that do work on commission and if they can lock a phone to a carrier to get their commission, they will and possibly without telling you. It's not an Apple thing, it's who you buy your phone from. BTW this is true with all smart phones, not just the iPhone.