re: Why do hospitals have their people send separate bills?

I totally get all that.

The one point that I get kinda lost is getting burned with an out of network charge from an in network hospital.

If a hospital is outsourcing, they should be dictating the pay terms which the doctor agrees to abide by while acting as an agent of the hospital. These terms are related to insurance contracts.

This expectation of the patient to ask every care provider if they and all of their subordinates take a particular insurance is absurd.