Triggering rollback when entitystate is changed from modified to unchanged

With this change, EF rejects pending changes on a tracked entity when it's status is changed from Modified to Unchanged.  
Can this code go further down between the existing StateChanging and StateChanged calls instead of being its own little island? Also, not directly related to this, but it seems to me that properties should be flagged after the changing event rather than before so that code can, for example, look at which properties are modified in that event. Do you want to do this as part of this change, or should I file another issue?