Eh theres a lot of mistakes with some of our stuff (moped is a scooter is a motorized bicycle as long as it doesn't have gears and is 49cc or less. Also does require license, but not registration, or insurance) but it doesn't really relate to the electric unicycle or any other state for the most part.
With that said....
This would be fun. Just need to either make the platform in line with the x-axis of the wheel hub to get rid of the tipping moment, or just go ahead and make it below the axis so its easier to hop on.