in talking to a fellow from a local military museum I discovered that they use this type to avoid having vehicles stored indoors with a tank of gas. they just move the GI can outdoors when they park the vehicle. They started this after coming in to the storage floor one weekend and discovered gas all over the floor as the regular tank had started to leak. Luckily they were able to clean it all up without a mishap. I plan to store mine this way.
