http://www.americanbar.org/newsletter/publications/aba_health_esource_home/aba_health_law_esource_1111_gold.html

The New Jersey Department of Banking and Insurance also prohibits physicians with a contractual relationship with a health plan from balance billing HMO members and extends the ban on balance billing to out-of-network providers who treat HMO members based on a referral from a participating provider or the HMO itself.13 After receiving a number of complaints concerning an Aetna policy that purported that payments received by out-of-network providers be considered as payment in full, the Department of Banking and Insurance ordered HMOs to "pay the non-participating provider a benefit large enough to insure that the non-participating provider does not balance bill the member for the difference between his billed charges and the . . . payment, even if it means that [the HMO] must pay the provider's billed charges less the member's network copayment, coinsurance or deductible."14 Here too, HMO patients are completely insulated from financial responsibility, excepting any applicable copayments and deductibles.

http://kff.org/private-insurance/state-indicator/state-restriction-against-providers-balance-billing-managed-care-enrollees/
http://blog.horizonblue.com/articledetails/stop-don%E2%80%99t-pay-doctor%E2%80%99s-bill-yet