Mathew I don't think you understand it yet, I think you know what parkour means now but you have to go out and practice the art as belle describes it to understand it. Let me give you a little background I have practiced gymnastics for five years, the first exposure I had to parkour was the video on avance toujours(lots of flips), I read the english version of David's le-parkour.com site which called parkour the art of movement.
So when I came on the online community and had people telling me that flips weren't part of parkour I was like WTF! Since I am loud mouth with a need to talk things out to understand them I quickly made my thoughts known and got flamed pretty hard. When davids defination came out I accepted out of respect for him but I didn't understand it. I didn't understand untill I went out and trained with the mindset he describes. It took me a little while for the mindset to actuall set it but when it did I realized that was parkour, when I have that mindset I don't flip, I don't wallspin, I don't do flair elements, the simply don't occur to me.
Which is not to say I don't train flair elements, I love to flip and do wall spins mostly I do them in the gym but at jams I will break them out or when I am just playing around outside with freinds.
Parkour is defined by the mindset of efficiency and speed of an emergency situtation. It doesn't matter if you never do anything but cat vaults, speed vaults and running gap jumps, if you don't have that mindset what your doing isn't really parkour. Its just the movements. When you have that mindset flair elements just don't happen. Which is not to say that people who train with that mindset never do flips while their out training. Ever get distracted while reading a book, get up stretch your limbs etc. Thats what it feels like if stop a parkour run and do a flip, my mindset has changed, I was doing parkour untill I was distracted by the desire to flip of that something. For the most part though that doesn't happen anymore, I only flip in the gym at jams or when I am outside specifical to practice tricking.
I would also disagree with you about free running I think free running is great, I don't like FRPK because it pretends to be something its not, free running, Yamakasi stree acro, street stunts their all great, they don't have to pretend to be something their not.