The EPA has, as you may know, made container manufacturers comply with their new standards. New fuel containers are miserable to use, at best. For years (pre-ethanol) i hauled auto fuel onto my airport and pumped it into my Skyhawk via a 12v. electric pump. I would also buy 100LL and pump it into a five-gallon plastic fuel container for use in small power equipment at home. I would use it in my boat as well as sell it, at no profit to friends who wanted to use it as a stabilizer in their fuel tanks. It was never an issue.
Today, I will drive my motorcycle onto my local airport and buy either 100LL or MoGas with a credit card. I also fill my boat which holds 50 gallons for it's inboard engine and, their are many airboat guys who also fill up. It's good alternative business for the FBO.
I would think rather than worrying about FAR's and EPA, you should be concerned about hauling fuel on the road in "un-approved" or improperly secured/stored containers by local or state law enforcement. When I hauled fuel to the airport, I did so in a 55 gallon drum that was secured to a wooden platform by strapping. I could also remove the tank by sliding it out and onto a platform I built for it. The pump was installed in the side bung. I would cover it with a tarp when hauling it. Out of sight - out of mind. I'd look for another FBO if possible. Obviously, the one in question is not interested in making money. Best of luck!