In over 25yrs of doing this.... this question and the "I heard" but never any proof of actual.... never once been stopped and asked to validate registration or driver license
There was one time we entered Oceano Dunes aka Pismo, there was a CHP check point inside the park. They were after unregistered ATVs. I had a 5th wheel at the time pulled by a 2500, WW tagged the 5vr at 14900lbs. The CHP asked for registration and what was in the trailer. Showed them the truck/trailer registrations, told them a Rhino and they sent us on to find camp.
Never stopped at Glamis or Dumont, only asked to show proof of camping permit.
Even now with MoHo and box trailer, over weight and length. NADA
not saying it can't or won't happen but in this time span you'd have thought by now something would have occurred if "i heard" was correct