I'm pretty sure it's an isolated issue rather than an issue with the coating process. DLC is widely used on knives and watches (contrary to what Archer1440 said above), and this isn't the norm. If it was a widespread issue, we would have heard about it by now. I wear my 42mm Black Stainless every day in a production environment. I haven't had any major bangs, but plenty of scrapes and minor bangs. No peeling or wear issues yet (since 5/14).
I hope you get your replacement quickly.
I really am hoping that it is.
I have two watches which are DLC coated and this is the first time that I have experienced such a thing.
I am still waiting for Apple to have me send in my band. I'll take some photos to see if there was a bit of change from last week's peeling.