JM is probably on a very short list of ski personalities, with enough clout, who could have pulled this off - that'd be taken seriously by the San Fran city council to allow the permit. If you actually think that any of the recent crop of "superstars" could have done it, think again.
20 of the top skiers and snowboarders got to show off for big money and charity and you're questioning it? It was late summer, and the newschool scene got a spotlight: I saw it on CNN for god's sake.
Get a clue. I have one for sale on e-bay, I suggest you purchase it...