I plated both sides of the OEM hitch pin hole when towing my toy hauler. The same egging also happened as described above.
If you apply simple physics of using a lever resulting in torque multiplication, you will see that you need to drastically derate an OEM with an extension or you will be severely overloading it.
My F250 with SuperHitch and SuperTruss had no issue with an 8000 lb enclosed trailer. Although I have since sold the Ford to upgrade to a Ram 5500, I still use the same SuperTruss with a new SuperHitch. Neither receiver or extension are showing the wear my OEM did without extension when pulling my previous 11,500 lb trailer.
Even going up and down driveway entrances would be problematic with a longer tongue and no extension on the receiver for us. I would hate to think what would happen if we traversed a wash to get to campsite. We don't four wheel with our trailer, but do camp in primitive areas where a long tongue would make contact with the TC underside.