And its legal in most states, unfortunately. Balance billing is when you use an out of network medical care provider and your insurance company covers $2000 of the $5000 bill. Then the caregiver turns around and bills you for the other $3000. How sneaky is that? But it gets worse. After a scheduled surgery you could find out the anesthesiologist, radiologist, and assistant surgeon are not part of your network could bill you for thousands of dollars.
The really super sneaky part is:
The medical care provider could be very quick to start billing you, send you to collections, and report on your credit rating.
And then sometimes your insurance company will pay all or a portion of the balance billing leaving you to undo all of the damage.
A portion of balance billing is illegal in Illinois and the is legislation in the works in New York. But if you get billed for teh balance, don't sit there, start dialing and researching to protect your bank balance and your credit rating.