I guess I can't join all the facepalmers here. The impending tragedy is never as obvious as it seems at the time, and I can't say it would have even crossed my mind that someone would get thrown over a wall. In downtown Houston, I could see the appeal of the garage. Open space, quiet, shaded...
Too bad - could have had another fellow rider enjoying the sport.
To urbanites it would make sense, some have no concept of "open space" other than a parking garage. I would also think it more likely that it was a scooter because that tends to be the typical choice of urban dwellers. So many of those urbanites seem to forget that a much larger world exists outside of the two mile bubble they have confined themselves to. I have seen them running all over the more urban areas of Denver, Austin and Houston.
My thoughts too.

Rookies need wide open space.
I know at least in Austin and Houston that is becoming harder to find as the design requirements mandate a landscape island in parking lots of no more than 100 or so feet breaking up the large asphalt lots like we grew up with. I know the autocross group in Austin no longer holds any events in Austin because of a combination of lots with these obstacles or lots with too much elevation change and property owners with the few seas of asphalt paving not willing to rent the lot out or absurd insurance requirements by those owners.