The retailer that sold the device to the victim said that she should have made sure that her HTC EVO Shift 4G had proper ventilation and should have been in a case that prevented the phone from touching her skin. The HTC EVO 3D, another phone in the HTC EVO series, had a history of overheating at times. But because this mostly occurred when the device was being recharged, the battery would appear to be the issue in that case.
In other situations, an overheated phone could be the result of the powerful electronics inside the device, all tightly packed inside a thin case. We've all experienced a hot phone from time to time, although we do have to say that to get branded by your handset requires a pretty high temperature. In this situation, the victim started to feel the phone getting warm before the lack of pockets forced her to tuck the phone into the waist band of her sweat pants.