Excellent point, Byrd_Huntr.
But backing up a bit, I think that an essential point to consider is "how do you gain the essential experience to judge the validity of local advice?"
You're not born with it. You won't get it in the dealership that sells you a 4x4. The only real answer is that you get it the hard way. Perhaps from someone who knows and has been there (ideally), or in small increments from say, weekend excursions in friendly conditions. Mostly, you learn a process. Some get it all at once, and the outcome is not generally happy.
Sue's point about crossing the freaking continental divide is valid. It's either gross stupidity or gross naivety. I'll bet real money that it's the latter. (I say this understanding the number of stunts I've pulled and survived, out of which I should be getting a bill from the squadrons of guardian angels assigned. So I'm not inclined to throw stones.)
My $0.02.
Sage advice...Some people are pretty good at imitating outdoors men/women in their banter, dress, and outfit. If an impersonator exited a capable-looking 4x4, approached a local, and said, "Is there a shortcut over the mountain?" A local may quickly size him up, assume he knew what he was doing, and then say 'yes', and point the way. My point is, that person could safely rely on local advice, but like dealing with a car salesman, it's because this person has enough background knowledge to tell good advice from bad, and enough common sense to react properly.