Here is what happens: The patient picks a hospital that is in their health insurance network. Then after receiving care, they get a large bill from a physician group that says they are out of network and any reduced rates don’t apply. Everyone seems to agree the practice should be banned (except the physicians). 
The federal HHS during these times have included a stipulation tied to emergency funding prohibiting surprise medical bills for Covid 19 patients. 
This leaves open the question of who is a Covid 19 patient? Beyond this stipulation tied to emergency Covid 19 funding, it does not appear there will be a legislative solution to the problem anytime soon despite the current healthcare crisis.
What can you do?
- Ask for an itemized bill always.
- While there is no legislation prohibiting the practices, that does not mean they have a legal basis to charge you. Did you ever enter into a contract? Without a contract, the provider may be limited to charging you the value of the services and they don’t have carte blanche to charge whatever they want.
- It may be for services that the hospital may have been required to provide to you. If so, then the services of any physician may end up being considered “in network”.
These are important issues to be explored if you receive a surprise medical bill.
 See https://www.npr.org/sections/health-shots/2020/04/17/837749925/in-fine-print-hhs-seems-to-have-banned-surprise-medical-bills-during-the-pandemi