When I first started smoking, I was only getting pretty good sativas and did have slight auditory hallucinations. I think it was from the combination of smoking a good sativa, being a beginner with no tollerance, and taking huge bong rips, because now, I'm getting amazing bud, sometimes indica, sometimes sativa, and I haven't had any sort of hallucination.

That being said, perhaps these people aren't exaggerating when they are describing how high they are, because we are just used to being high, and it's no big deal, but to them, they could just be occasional smokers, or first timers, and could be getting the high of their lives. Come on now, we all remember the first time we got completely blazed and how amazing it was.