Gray area
In NY, the official guidance on the NYS DOH website is that an out of network provider MAY balance bill. It does not state an out of network provider MUST balance bill. I had a sticky legal situation awhile back at a previous employer. We ALWAYS charged the patient deductible and co-insurance responsibility but did not balance bill. The insurance company's contention was that by not balance billing, we were overstating our R&C on the bills. They claimed over time, our bills would artificially inflate what they consider R&C. As a result, they processed our claims differently which resulted in us not getting paid at all if the claim was less than deductible, or getting paid 64% of R&C instead of 80% of R&C if the deductible was already met. When we initially balked (and even incorporated a lawyer into the negotiation), they advised to bill the patient the FULL amount, and they would then reprocess to the full R&C.
We had a consultant come in and analyze the entire situation over a period of MONTHS. He stated we would not be artificially inflating the R&C as the insurance claimed if we notified the insurance of our intent to accept R&C. The final consultant recommendation was to add onto all the out of network bills to insurance "DISCOUNT PER THIRD PARTY NETWORK, R&C CHARGES, OR NEGOTIATION." We probably wound up paying almost $100k for that advice. AND the insurance would not recognize this anyway, and continued to process the claims with the reduction. It never got resolved - we eventually went in network.
I STILL contend it is not required to balance bill as long as you are charging the deductible & co-insurance. However, the insurance carrier may see it otherwise.