Ok so lets see, I am in the middle of a major power outage and the only way to get gas is with a pickup and I don't have one so I guess I am out of luck because some old worry wort said it was unsafe..I think not. People have been carrying gas in metal cans no less in the trunk of their cars like forever. I drive a Model T and am sitting on the gas tank!
I do however have a pickup and per Oregon law fill the cans on the ground to prevent static discharge and strap them in place so they don't slide around on the plastic bedliner before I leave.