Having the wheel "lock up" is a mischaracterization of the failure mode under loss of power. The problem is that loss of power while you're on a reverse pendulu

Having the wheel "lock up" is a mischaracterization of the failure mode under loss of power. The problem is that loss of power while you're on a reverse pendulum means that you're leaning forward, and the device is no longer able to stop you from extending the lean by giving more power and speed to bring you back into balance. Any device which operates as a powered reverse pendulum will have this property. Segway was the first, and there are plenty of other "hoverboard" or "unicycle" style designs which act similarly. The differences with the Onewheel are thus: 1) It's a skateboard orientation, so if you don't have the muscle memory from skateboarding you won't know what to do when it starts to bite the ground. Front to back orientation is more intuitive. 2) It's faster and higher powered than most alternatives, lending more risk of being beyond the threshold which you can reliably transition to running if it loses power. That's it really. It's a more sporting device with a higher learning curve and a bigger risk envelope. It is advertised as such though. This is a thing that's made to shred in all terrain for people who are daring enough to deal with the risk. They're making manned multi-rotor copters where one motor failing mid-flight means you fall right out of the sky, and that's a pretty likely death. Sporting devices with power failure modes that have no easy recovery are not unprecedented in other categories either. You have the same problem with classical helicopters if you're below the auto-rotation altitude or are not skilled in auto-rotation recovery.