Storage in transit for LPG

For years now I have always carried my 2nd 6kg calor lite bottle in the car. (Suiably anchored down of course) This has been purely for the purpose of getting an acceptable nosewieght on the hitch. It occurs to me however, that I am effectively carrying a mobile "incendiary device" in the car. Does anyone else do this, or am I alone in the somewhat foolish act?

Peter