Since it happens quite often out there, I think so too. I also think the family in Hong Kong may have accepted that as a possible answer. I think she may have been annoyed, over-heated, under-hydrated and probably badly wanting A/C. I think she walked past the truck and down the dirt road off Kelbaker, probably for a potty break (having failed to find the hidden key and now being even more annoyed).
In that state, people are vulnerable. People can pass out very quickly from heat, and one of the symptoms of impending heat stroke is euphoria and/or agitation.
So, I'm with you, Roses, at this point. I do think there are aspects of the story that speak to negligent behavior on the part of the elderly husband (he had all the water, he didn't stay by her side) but perhaps she walked away quickly. Perhaps his sense of time was faulty and she was out of his sight longer than 3-5 minutes.
At any rate, there's been no further criminal investigation of any kind that's been visible to the public. I contacted several reporters, stayed in touch with them, talked to them on the phone, and they could get no more info from LE. Case isn't closed, but it is obviously cooling off to cold.