In the Western US, there are a lot of roads that range between unpaved but well-graded and generally fine for passenger car use to serious high-clearance 4WD in good weather only. In my experience, Google Maps doesn't routinely send you down seriously questionable roads. But, if you drive around those areas, it behooves you to really understand the range of roads out there and be properly cautious rather than blindly depending on GPS--or, for that matter, a map.

The biggest problem is really that a lot of people come from areas where road is 99% equivalent to passable by passenger car under most to all weather conditions and seasons. That's just not the case in many places, e.g. Death Valley.