Blame the manufacturers ?
As both Segway and Xiaomi make the devices for personal non-commercial use and provide instructions that the commercial operators are not following (inside storage and inspection before use), I do not see what blame should be attached to the manufacturers. Their inclusion in the lawsuit seems just to be a way to hopefully get a bigger payout than is justified.
Blaming the manufacturers in this case is like blaming the maker of a sailing dingy because it sunk when the idiot user tried using it in a grade 5 hurricane.
Biting the hand that feeds IT
