Wow that video made me feel a bit ill. My 650 tank is bolted to the chassis, and it on the back of a double cab pick up, so it would have to break free from the chassis and go through the second row of seats in the cab before it hits us and I've not worried about keeping the speed down, just as long as I'm in the limit. However after seeing that video I might drive a bit slower. Definitely keep it safe, after all thats the whole idea of wfp.
Simon