Unfortunately I didn't manage to record my single encounter with that cheater. Moonwalking's normal yes, but that single cheater I encountered outran (while moonwalking) 2 players on Chocobos. Yeah of the 6-7 players present at the time, 2 were on Chocobos. After my sprint wore off I mounted but it was pretty evident that I'll never be able to catch up with him and so I gave up.

Pretty sure it's similar to the speed-hacking gathering botters used in the early FFXIV days, where they zip along the ground at alarming speeds.