This is what happened to an acquaintance of mine. After being a loyal and accident free customer for over 40 years, State Farm denied that she suffered a neck injury and TMJ as the result of being rear ended by an uninsured driver.
It would cost as much to fight the case as to settle for about $10,000 less than the usual for this type of injury. State Farm spent more on their attorney, IME, deposition, and mediation than they paid to their injured insured. Their attorney drove away from mediation in a new Porche.
Be warned. I told her about my insurance company, Amica.