I seem to be hearing conflicting news about this so can someone please clarify. A friend wants to buy a new iPhone, she will use an O2 sim but will be travelling to India and therefore will be using a local sim whilst out there. It sounds like iPhones bought from certain places, even as unlocked, will become locked to the network of the first sim used. Phones bought directly from Apple apparently don't suffer the same fate but Apple claim certain sims/networks will lock the phone to that sim. Please enlighten me 
