I know public use devices have their own problems with reliability, but I did almost cause a traffic accident a couple times over the years. Every time, the scooter's accelerator lever got "sticky" due to repetitive (mis)use, and would sometimes not go all the way to 0 when released. Stuck at ~10%, the scooter would brake normally and remain at halt under my weight, but the moment I stepped off it, it would suddenly launch itself at the cross traffic.

It's these little things that get you. The scooters all have some kind of debounce logic, disabling the accelerator until you're moving sufficiently fast - but the logic doesn't kick in when you stop without releasing the lever. A little bit of redundancy would've helped here.