This is not an uncommon practice. I work in a hospital and the group of ER docs may not participate, so there is always that chance. And, it may be that , as in our hospital, all the docs are from the same "group", that none participate in-netowrk, but there is supposed to be a clause or waiver with your insurance company to get around that and the insurance company should be the one to handle it.
I had this happen, as I say I work in a hospital, as a contractor, but my insurance has this hospital as a provider. I had to have an x-ray, and the radiologist that read it isn't in-network, well that isn't up to me to keep up with, because likely none of them in the group is and even so, they wouldn't hold my x-ray to be read by someone else if they were. Well, I wasn't aware of this until I got my EOB and a bill that didn't match up, so I called the Ragiology group and spoke to a really nasty rep that didn't know what she was doing. I called the insurance company and the really nice rep there said they were supposed to file it with the waiver (becuase the primary service provider, the hospital, is in-network, that makes the service in-network) and she took care of it for me.
As large a company as BCBS, you would think one of their reps would have had the right information.
Suzanne