I am such a #hypocrite but to my excuse there are probably few places more beautiful than #elretiro to give it a try.
My resume: Fun to zip around in the park and didn't see them laying around on the grass like in SF. Was it an interruption to the park visitors? Definitely, but only speed wise - there are already many non-motorized vehicles such as go-karts and bikes everywhere. However, now I even less think that it's a good idea to bring them back on SF streets from a safety standpoint.