The sad thing is that they have to put this sign up at all......
People count on their GPS and 4WD to much!
You should have maps, common sense and knowledge of local conditions.
4WD drive should be the exit strategy.
Not a means of thinking you’re invincible!
I have never seen such a warning sign. You're right,not knowing your vehicle and the terrain can get you in some nasty situations. I see more and more SUV's stuck while on my treks to Death Valley. GPS is a nice tool but like you say, no replacement for common sense!