shipping in such a way as to put its life in extreme danger, while very likely creating whatever circumstance led to its untimely demise
That is a far, far reach. We do not know if in fact this critter was overheated, whether a heat pack was called for, etc. At the very least the buyer is responsible for some contributory negligence for putting the critter out in the sun if she thought there was a heat issue.
I have sent a link to Reptile Express, I hope Debby will weigh in about the heat pack issue.