I can understand that CAPs need to be monitored for effectiveness and possibly revised if they are not, but to assume that a CAP (or even a revised CAP) would prevent the recurrence of a violation is not realistic.  There are too many variables, including human behavior.  This statement in itself is proof that a systemic plan is not always required.  No one can guarantee that a problem won't occur again, regardless of the plan put into action.  Having to guarantee a CAP (or revised CAP) will prevent a problem from reoccurring seems to be an impossible standard to meet.