One modification to this scenario...
Pre-existing condition was seldom used proactively by the payers. It was almost always used retroactively.
So, in your auto accident scenario, it would be like you being in an accident where you were injured. Your hospital bill was $250,000. After receiving the bill, the auto insurance company then requests your driver record from the State and they find that you were in an auto accident 20 years ago. They then retroactively cancel your insurance and deny your current claim because you had a pre-existing accident.
Anything can be a pre-existing condition. Your physicians have you sign a "Release of Information" document that allows your insurance company to request your records without your knowledge or specific consent. If you get cancer, your insurance company might request those records and assign them to a reviewer. If they were to find a positive HIV test or that you were on a medication as a child that was associated with cancer, they can deny your claim citing a "pre-existing condition". Because their "reviews" were usually triggered after diagnosis with a serious illness or after a medication was prescribed for prevention of a recurrence, the patient is left uninsured.
Something that got lost in the flurry of regular repeal that the Republican Congress has been busy with while Trump keeps everyone distracted is a bill that one of my favorite Congresspersons, Rep Virginia Foxx of North Carolina, slipped under the radar. Thanks to Mrs Foxx's efforts,
if you refuse to submit and provide genetic testing results to your employer, your employer has the right to increase your insurance premiums. By providing your DNA testing results to your employer, you will open new possibilities for pre-existing conditions that you didn't even know you had.