Reimbursement happens when "you" have to pay the entirety of the hospital bill WITHOUT any insurance (meaning the hospital does not accept your insurance plan). Otherwise, the hospital/doctor's office ACCEPTS your medical insurance and abides by the "Guarantee of Benefits" GOB that you will provide them. In that case you will only pay what is typed on the GOB. It could say you PAY NOTHING, or you pay 20%, or you pay a CoPay of $10 or whatever. The GOB states exactly what you will pay and the the Hospital/Doctor's office sends your Medical Insurance company a bill for the remaining part and you WILL NOT hear anything else from the Hospital or Doctor's office because it was pre-approved on the GOB.

If you end up going to a hospital for instance in an emergency situation like a car accident where you can't contact BCBS/GMMI for instance, and is not approved for any medical procedures. You will have to pay the entirety of the bill before you leave the hospital. And then when you return home or to your hotel, you will take PDF cellphone photos/images of all the invoices and treatment documents and send them to a link on your insurance website and they will deposit a check into your bank account within one month (according to the website), but in reality it only takes 2 weeks.

That's why its good to find a hospital and doctor's office that's already approved with whatever plan you get so you never have to pay up front.