It’s very likely that the hardware and/or firmware was not designed to meet a quality standard appropriate for the associated customer risks.
I’m guessing the difference is that you dont have to sign a waiver for onewheel riding?
If a chute doesn't open because of a manufacturing defect, that creates liability for the manufacturer, too.
AFAIK there are no such standards (mandatory or voluntary) applied to Onewheel’s devices.
They could have voluntarily applied hardware and software standards from other safety fields (e.g. automotive engineering), but they apparently chose not to.
As the peer commenter said: move fast and break bones.