Cargo cameras, thermal and otherwise (that can sense smoke thousands of times more sensitively than smoke detectors) are a good step IMO. It won't stop a fire, but it could give you immensely more data than is usually available these days. Some carriers have already done this, but it needs to get more comprehensive. That could tell you the difference between the "15 minute" scenario, one that may not be as critical, and one that may be more critical.