At this point I'd say it's imperative that some kind of quick hardware top plate disable function is implemented, and ASAP! Make it a Shift plus something - ideally that would be a combination of shift plus top plate, but since the top plate is probably malfunctioning that's not the best. It has to be fast. No menu diving. The thought of 250 people standing around (and probably booing) while I figure out why things just suddenly stopped for no reason scares the crap out of me.