> "The real danger of allowing smoking on a hydrogen airship - was the risk of a fire"

Maybe. They had diesel engines, 240 Volt and 24 Volt electric generators, 200 Watt battery powered radio transmitter, backup radio transmitter, a 5.7 million candle power searchlight, an electric oven and hob galley. It's not like there were no risk of heat or combustion anywhere else on the airship.