I've never had this experience, nor have any of my friends. For the sake of clarity I want to emphasize that we are talking about PIP coverage and NOT coverage of another drivers policy following an accident.
One. Successfully to the tune of over 10K, many years ago.
None of my friends nor myself have ever had this experience. The closest situation to this I can recall was when I totalled my truck and the insurance company tried to undervalue the replacement cost. All I had to do was provide three examples of similar vehicles and the asking prices for them. I did not think this was unreasonable at all. I recovered the fair replacement value of the truck.
Again, none in my experience.
Maybe my experience is outside of the norm since I researched insurance companies before spending my money and I am well-versed in insurance law. I am covered by State Farm.