WHILE I believe apple has a right here, who would want someone selling something with your trademark, I do think they should leave the kid alone.
He sold conversion kits to something Apple would not release.
And there were quality control reasons that Apple was not releasing it.
And you had to have an iPhone to do it, so Apple sold a iPhone, and the kid made a bit of cash for his smarts on knowing the demand of a market.
Yes, the customer did buy an iPhone to do this. A BLACK iPhone.
Now what happens when this customer has a problem with their iPhone and need a replacement at the Apple Store? You think that transaction is going to go smoothly? You think Apple is even going to honor the warranty? You think they system would even allow them to? If you're phone is firmware modified (jailbroken or unlocked) they won't touch it. What makes you think that a hardware mod would be easier to warranty? White iPhones and black iPhones have specifically different model numbers. You think the customer is even aware of this?
So even if Apple swaps it out with a replacement, that replacement will NOT be WHITE. They cant swap out one model number for a different model, unless of course the original one is discontinued. You think this customer that bought this conversion kit even realizes that? No, they will be upset at who? Apple for not honoring the warranty of this iPhone. So, yes this will put Apple in a negative light for this customer.
And although Apple does make quality products and I haven't had to get mine replaced before, remember, these were factory sealed phones when the customer purchased them. Sure, the kid may be smart enough to take them apart and swap out the casing to change the color, you think these will be as perfect looking as factory sealed? These a potentially more prone to having issues than ones unmodified or opened.
Besides, if these parts were not acceptable for Apple to use, since we all saw the threads of "light leaks" as being the reason they weren't up to standards for Apple, whats to say this customer won't be in the Apple Store trying to get a replacement because it has light leaks, or some other defect prone to these parts?
Now that Apple sells the white version again, i am sure his demand will go down.
Let the kid win.
Its a lose-lose for the customer potentially. They will be mad at Apple for not being able to honor the warranty, not at the kid that modified it.