The rentals go 15kph. That is hardly an issue. Bicycles and skateboards can go just as fast (even faster) and are just as dangerous. I've seen these in a few major cities in the US and abroad. The issue isn't really with the speed. It is with people dumping them wherever they want, not worrying about propping then up neatly out of the way or on the kickstand. Drunks operating them is also an issue...but this is an issue with any mode of transportation.