Sometimes it is an oversight, sometimes it is fraud. How many times before it is fraud or not?Explain

How many times have you received a bill from an inpatient or outpatient stay that was either upcoded or inaccurately coded.  If downcoded, most people don't bother bringing that to anyone's attention and hopefully Case Management and Audit picks it up, but when it is upcoded and Medicare, Medicaid or a Managed Care Payor picks it up, there can be serious consequences. 

Sometimes it is an oversight, sometimes it is fraud.  How many times before it is fraud or not?Explain