Wow, I thought this thread was a joke when I read the title. And a poor joke at that. @nukegoat if you've ever seen the results of humans that have survived accidents involving gasoline burns, let alone the remains of those that didn't, you would abandon this ridiculous idea. I don't care how many "degrees" you have in any field. And I don't care how many "safeguards" you design into it, it's not worth the potential danger to the occupants for carrying around a few extra gallons of fuel. I'm no saint, I've foolishly carried extra fuel inside my rig and gotten away with it when needing extra fuel for a trip. But looking back, to what I exposed myself to, I shake my head in embarrasment. Since then I've been blessed to install a LRA 24 gallon aux tank where the OEM spare was stowed. No it's not foolproof or totally safe, but it's engineered with a time tested design? You can't see all the hazards coming your way, but you can use common sense to avoid exposing you and your rig's occupants to unnecessary risks.