I have an anecdotal note on this. Some years ago I was seriously injured in a bicycle accident, in which a car hit me on the road. The hospital and medical charges ensuing were very large, though not as large as some others I'm sure, but many thousands of dollars. I had health insurance, but because a car was involved, my health insurer claimed the car's insurer should be liable, and simply refused to pay anything, forcing me to sue the driver, whose insurance company of course stalled and balked for years. Now it's also true that what my insurance company did was probably if not illegal at least unethical, but the only way I could have handled this was to sue them! During the couple of years that this dragged on, the hospital relentlessly dunned for its fees, finally sending the bill to a collection agency, even though my lawyer, who knew the law, informed them multiple times that this action was also illegal while the case was under litigation. Eventually a barely-sufficient settlement was negotiated with the driver's insurance (she was quite emphatically at fault here), and after some negotiating by the lawyer to reduce the fees, the bill was paid.