This all depends on your personal operation.
I fly an annex 2 Permit aircraft off a farm strip, with no fuel facilities at all on site. A local bimble south requiring a fuel stop diversion 20 miles north or east first with £15 landing fee is hardly economic.
It's a risk I know, in an estate car (US station waggon) cans upright in a fitted box.
I've had the occasional leaky can that I can smell en route, but fixed as soon as possible, and I don't throw cigarette butts over my shoulder!
Never had a problem with the Continental c90 running it for ten years. So far so good!!
Chuck glider beat me to it.