If I understand this article correctly, they buy a new iPhone, replace an expensive part of it with a cheap knock off, return the "broken" phone to have it replaced and finally sell the expensive part as well as the replacement phone.
Even if you sell an iPhone in an unopened box I guess you lose at least 20 % of what you paid for it. I don't understand how e.g. stealing the screen or the battery of the phone could cover that cost (no less the cost of the work of taking out the battery or hiring people to visit the Apple Store and so on).
What am I missing?
Edit: Why is my question put on hold while a similar generic scam question like this is allowed?