This happened couple months ago. It was my daughter's iPad (and before that it was my wife's). I got fed up that it was randomly shutting down. I didn't care what it would cost to repair it. It did not make sense to buy her a new one as iPad Air 2 was still more than enough (apart from shutting down issue).
The only person who had access to that iPad apart from myself, my wife and my child is a BestBuy technician, who took it away from me to inspect it in the store and then returned and said it was a battery issue. He said that it would be best if I shipped it to Apple myself to get a faster turn around. I don't think he jailbroke it, but perhaps, whatever idiot inspected it at Apple, saw traces of testing done by BestBuy tech and decided that I "misused" the device.
I will never let BestBuy lay their hands on my Apple devices going forward.
If anyone from Apple would be reading this, here is the repair ID: D497535965