It ain't no urban legend, as I'm living proof. They won't (aren't allowed to) pump it into your vehicle, but one can take jerry cans and fill them up here in Brantford and other airports that are small municipal operations with lots of privately owned aircraft that have the potential to land on private airstrips. The issue is that those craft need the higher octane and the low lead for engine valvetrain lubrication, and so people can get it delivered by truck to their private airstrip's gas tank (up to 500 gallons), or come and fill as many portable cans as they need to, and if they're forced at any point to use non Avgas, they can experience engine failure, and that's a big no-no in the aviation world. There are only two kinds of landings - good and bad... lol.
I take two or three 5 gallon containers and do it all the time.
For the wagon (which pings ALL the time on just regular 91 - 94 ethanoswill we get), I use one 5 gallon container per tankfull. It loves it, no more ping, and a noticeable boost in performance.
Yes, it costs more, but that's the price of fun in my book. For a daily it would be cost prohibitive even doing that, but hey, try it, you'll like it!!