Just this week in Vantaa, Finland three 12-year-old girls piled onto one of those electric scooters you subscribe to with an app and proceeded to get run over by a car at a crossing, killing one of them
The app is supposed to have an age restriction but it's easy to bypass and you're not supposed to have more than one person riding on one, which people routinely ignore
I hate seeing kids and teens speeding around dangerously on those fucking things and then just leaving them laying around on high-traffic bike routes because they don't give a shit since they treat the scooters as completely disposable
Fucking awful bazinga-brained Silicon Valley-ass idea and business model. Actually, there are also bikes you can use with an app but curiously you don't see kids doing reckless shit with those, almost as if electric scooters were uniquely terrible 
Where I live I've seen a couple of abandoned rental bikes but typically people seem to use them properly. The people that use them seem to be mostly adults, though whether this is because of the app being more effectively age gated or the bikes being adult-sized, I'm not sure
I also assume a bike is just less attractive for random joyrides
Edit: they're also less available, since you can only get them from docking stations spread around the city that you're also supposed to return them to