This reminds me of the classic industrial accident involving a large, pressurised storage tank. There is a man-sized door to allow access for maintenance and a pressure gauge. The maintenance man is supposed to wait for the pressure to fall to zero before he undoes the heavy steel latches. It is a big tank and he gets bored with waiting for the pressure to vent. The gauge says one pound per square inch. One pound doesn't sound like much so the man undoes the latches. Since the force is per square inch it is several hundred times larger than expected. The heavy door flies open irresistibly and kills the man.

I'm not seeing how the parable helps one be less wrong in real life. In the parable the victim has seen a dog taken by the dragon. If the maintenance man had seen an apprentice crushed in an earlier similar accident the experience would scar him mentally and he would always be wary of pressure vessels. I'm worrying that the parable is cruder than the problems we face in real life.

I don't know more than I've already said about pressure vessel accidents. Is there an underlying problem of crying wolf; too many warning messages obscure the ones that are really matters of life and death? Is it a matter of incentives; the manager gets a bonus if he encourages the maintenance team to work quickly, but doesn't go to jail when cutting corners leads to a fatal accident? Is it a matter of education; the maintenance man just didn't get pressure? Is it a matter of labeling; why not label the gauge by the door with the force per door area? Is it matter of class; the safety officer is middle class, the maintenance man is working class, the working class distrust the middle class and don't much believe what they say?