Every other car I've recently owned has had a tethered gas cap of some sort, but they all seem to be designed as an afterthought — their short length dangle the cap up against the bodywork of the car or force you to balance it somewhere closeby the filler flap possibly marring the paint. The Smart's looks to be one of the smartest — a springy accordion cord that allows the cap to dangle straight down avoiding contact with the bodywork completely. Simple and functional.
