Woody nailed it.
As somebody who does both free-running and Parkour (if you want to say there's a difference...some certainly will insist), I'd say that the inclusion of Parkour in the games would certainly be a controversial inclusion. Particularly if it were to be judged on technique and form, as this would detract from something also central to the movement: personalisation.
I was actually thinking about this earlier today so I'm stoked to see the thread, and just earlier in the week saying that good traceurs could probably give the pros a run for their money in the steeplechase. But something more free-running, I thought that would look absolutely sweet although on further consideration, I don't think the community would be ready for that for a long time yet.
It might in the future seeing as the community will grow and change and so too will the dynamics. The original insistence on spontanaeity and independence may be lost in the subsequent commercialisation and organisation of the forms. As somebody who did these things before he was even aware of Foucan and Belle's coinage, I'd say that they already took that double-edged step by naming techniques, forever embalming free expression in the bounds of formality (something akin to what Sartre did to existentialism).
The other concern is that parkour and free running is demonstrably more dangerous than most of the other sports, frequently resulting in severe injury and sometimes death. If an additional competitive pressure were taken, you can be sure that a lot of people are going to die, and the IOC certainly can't have that.
