Otherwise, you could end up over-reporting.
Guessing at definitions for reportable injuries of unknown source or origin is an idea rife for F tags. You only classify an injury as such when it meets both of these conditions, according to the State Operations Manual:
• The source of the injury was not observed by any person or the source of the injury could not be explained by the resident; and
• The injury is suspicious because of the extent of the injury or the location of the injury (e.g., the injury is located in an area not generally vulnerable to trauma) or the number of injuries observed at one particular point in time or the incidence of injuries over time.