The DIII-D digital plasma control system (PCS) has been adapted and used at a number of tokamaks around the world over the past several years. Implementations of the DIII-D PCS at KSTAR and EAST in particular have made use of, and improved upon, the methodology for off-normal event/fault detection and response that was originally incorporated into the DIII-D PCS. This work discusses the lessons learned implementing and installing codes for detecting and responding to off-normal events in both plasma discharges and tokamak systems. In particular, we discuss the implementation details for codes at DIII-D, EAST, and KSTAR, and discuss how those experiences are being incorporated into a proposed finite state machine architecture in support of ITER research at DIII-D.