I found the guide below the other day at work after running into another consumer who didn't seem to understand the importance of staying network. It's a long one but worth reading if you want to learn the importance of staying in network.
At least it's a lot longer than my succinct spiel on the topic: "Stay in network, or you're really screwed, from Sunday to Saturday. You'll regret it. Just don't do it."
On the positive side, it does provide a tip or two if you can't get the medical service you need in network.