OK howzabout 95% of the power pedestals found between Guatemala, Belice and the EUA? Are the receptacles in your home grounded correctly? What do you do when overnighting in your rig when you know the receptacles are not grounded?
Not all parts of the world use a grounded system. Two wire appliances do not have a ground wire. But most RVs are wired with a ground system so they should only be connected to grounded outlets - which are not always available - which is why we carry a ground rod for temporary grounding. We do not run heavy appliances if we do not have a decent ground.
In the US the minimum requirement (last time I read the code book) is for an 8 foot long solid copper rod 5/8 inch in diameter. The rod must be pounded into the ground vertically - never horizontally. We used to use "chipping hammers" (mini jack hammers) to mechanically force the rod the full depth into the ground. It is next to impossible to pull one out.