Two specific instances: 1) The anesthesia group in the in-network hospital is out of network. We always get a $5k-$7k bill after that. We have to go like 3 months of fighting with the insurance and resubmitting for them to be like, “right, you went to an in-network hospital.”
2) This is my favorite one. The ER (at the same hospital) is staffed on the weekend and some weekdays by effectively freelancers. So they’re out of network. Same fights with insurance about in-network nonsense because these docs are out of network. So next time I hit my 7yo with his epipen and call 911, I need to call ahead to the ER to find out whose working today.