There are plenty of times when in/out network is an impossible thing to determine or plan for.
I had an out patient surgery about a year ago and while my doctor and every admin I talked said that everything would be in network, I still had someone sneak in who was supposedly out of network.
Then came the bill of what should have been ~$300 was around $2500. I got that BS waived only by called my doctor's office and talking with them about it. Once we talked it all through, the nurses called the _head management of company that ran the out patient surgery clinic_ in order to get it removed. It feels like people have to do you favors in order to get your actual correct billing.
Our health care system is so royally f'ed in the U.S. It desperately needs fixing and I hope it does before something serious happens to myself or my wife because it's currently feels like gambling with ruination. No $2.5k isn't ruination but health care is the only thing in this country where I go in knowing NOTHING about what my final bill will actually be.