Well, a couple of days after my initial visit, my insurance company had someone call me and say "hey, just so you know, we authorized your MRI at Stanford, and we will cover it to the tune of 90%, but the price is higher than most in your area, so we want to make you aware of more affordable options." I'm a pretty stubborn person, and I hate feeling like my insurance company is trying to screw me, so I thanked him for his time and declined.
Then, after a few minutes, I started coming to my senses. Yes, I have good insurance. Yes, they'll pay. That said, should I really have a $5000 MRI instead of a $750 one? Yeah, I can afford the $500 copay, but do I really want to? I'm used to just taking whatever services are recommended, but this time I went ahead and cancelled the Stanford MRI and took the $750 one instead. Saved myself some money, saved my insurance company a lot of money, and sent all of those dollars to a provider giving me a service at a reasonable cost.
(sort of related, my wife was recently in an accident where she went to the Stanford ER and was in the hospital for almost a week, plus some surgery. We accidentally gave the wrong insurance info so of course I got an Explanation of Benefits from my insurance company a few weeks later, saying "you owe your provider: $200,000" which is quite a funny thing to receive. Maybe it it was $20k it would be stressful, but once it hits the hundreds of thousands you realize you're not going to pay for it anyway. Amusingly, I think it didn't even include the surgery, or at least not the anesthesia, so I'm quite sure the true cost was north of $300 or $400k, and wouldn't be surprised if it broke a half million dollars after followups)