Getting my last few teeth extracted and graduating from a bottom partial to full dentures. Set an appointment with the oral surgeon, who called me back the next day.

Dentist Office: "I see you have Medicare Advantage,. We're not sure if they cover your extractions 100%, so you may have out-of-pocket charges."

Me: "I called my insurance company yesterday and asked them. They cover them all 100%."

Dentist Office: "Oh, okay, that's good. I see we'll be giving you Nitrous Oxide. You probably didn't ask them if that was covered. Did you?"

Me: "Actually, I did and it is also covered 100%."

Dentist Office: "I see. Well just so you know, insurance companies often have strict guidelines on anesthesia, so it's possible you may have some out-of-pocket charges on that. We'll just have to see."

Me: "Well, I'd better not, because my insurance company assured me that everything was covered 100%, so I'll want to see documentation. But thank you for calling."

I absolutely believe they do shit like this to test the waters for a chance to double bill their patients.