It seems that enough of us here in the Cellar are receiving health care to ask this:
After a medical appointment, do you carefully read what is available from the provider, such as office visit summary and after visit orders?
I do and I always find things that I am being billed for that simply did not happen.
The basis for these fictitious encounters is what is called "up coding," otherwise known as fraud.  
It seems to be ubiquitous and simply ignored in the world of medical insurance, including Medicare.
I have more on it if there is any interest.