About 15 days ago I purchased a 4S from a apple retail store paying full price. I cut my tmobile sim and inserted into the phone and it recognized the network without having to do any sync with PC or getting the unlocked message. So does this mean my phone is unlocked? Can I use it on any Carrier of my choice when I travel abroad? To be sure that I have an unlocked phone should I return my existing device and get an "officially" unlocked one from Apple? Or continue with existing phone I still see posts which say how to use the 4S on tmobile listing 10 or more steps to follow to make this work. Isn't it obvious and straightforward?