I have not tried this yet but this looks like a good feature to implement for every process that you design to prevent premature termination of process when unexpected data results in line rule conditions to not match.

In the Process, check off “Enable Process Finish Rule”

Create an activity named Complete with a Server event that updates DataField Completed to Y.    Normal end of process needs to go to this Complete activity.

 In the view code for Finish Rule, check to see if Datafield(“Completed”) = Y, if not, throw an exception to alert Workflow Administrators.   (exact code TDB, should be generic enough that can be placed in DLL and shared with all workflow processes)

K2.AddToErrorLog = K2.Configuration.IsErrorLog;
K2.AddToServerLog = K2.Configuration.IsServerLog;

http://help.k2.com/helppages/k2blackpearl1390/webframe.html?page=Finish_Rule_Exception.html

From Help:
"The Process Finish Rule Wizard allows the process creator to insert custom code within the process Finish Rule. The Finish Rule determines the conditions under which the process will complete. If the conditions are not met, the process will not complete."

From Support:  The FinishRule code only checked when there are no more activities that the process can follow.