I dont think that the pot got contaminated... It seems that each bundle is wrapped in plastic wrap which would protect it from the elements. I also disagree that people are smoking something which they don't know what it is. Pot is pretty simple to see and judge whether it is pot or not. I mean just look at a photo of a marijuana bud, smell it, and you will know what it looks and smells like. It is not like powders or other drugs where one can substitute something else for the real thing.
The thing I don't understand is who buys this mexican trash? At least here in California we have real good marijuana and we have no need for that crappy mexican stuff.