D.P.
Balance billing no nos only applies to providers who belong to the network. Let say you have PPO and your ENT is a preferred provider for that network, meaning he is contracted with your insurance company to accept x $ for the service provided, he should not be able to bill you for the remainder of the bill.
Edit /add
Melanie is right there are other things you may be paying for but this does not fall under the definition of balance billing ( although it may be what you are referring to and are paying for). These are referred to as copays and deductibles.
By definition, deductibles are the $ amount you have to pay for before the insurance share of the bill kicks in.
Co pays are the percentage $ amount you are responsible for.
Copays and deductibles vary from contract to contract depending on what contract you have.
To know if you are being balanced billed:
Check your EOB (Estimation of Benefits). This comes from your insurance company. It should list the fees, applicable deductible and copays as well as what your insurance pays. If you receive a bill from a provider that is basically the difference between what is paid by your insurance and what the balance in fees (after deductible and copay) then yes you are being balanced billed.
Scanned your article BTW and there is a good point --some consumers assume that just because the facility (hospital) is a par facility provider does not mean the provider (doctor) is. Therefore the doctor can balance bill. (This may be the case for Rebecca P.)
As far as the ADHD testing, chances are it is not a benefit. In my experience these things are rarely if ever paid. And yes, the insurance co can take back monies paid.