I understand that when you need to go to the emergency room, you don't really have much of a choice. Please understand that my care at this institution was probably worth four stars. My opinion of their billing practices was responsible for the loss of stars.
Your experience may or may not be different;
While I was still in the ER the financial person came to my bed and asked me to remit over $2000 on the spot. When the paperwork slowed down, my insurance company sent me an EOB indicating my responsibility as only $1000. So I called their billing department and spoke with a very nice lady, who began the refund process. She also said they routinely don't return the overpayments to the patient unless it is requested.
The only thing going through my mind right now is: WOW! This might be part of what is wrong with our health care system. If you need medical assistance, this isn't a bad place - just watch your money.