I can see how a horrible wreck could make it look like it's flipping over, depending on the view, but in all reality, it probably isn't. Somthing fun I remember doing on GT1 to test the theory, (all the way back in highschool, wow!), is I bought a Tureno, (why can't they use the US desginated names and then let us drop J-spec engines and stuff in. so many poeple see that name and never take it for a corolla

). anyways, I bought the Tureno, decked it out and tuned it's suspension so that it would drive around every corner on the outside tires only. Looked pretty funny on replay, but you couldn't flip. was fun to see how far out of the corner you could keep it on two wheels tho! (haven't tried on GT3, what happened to buying bodykits anyways!!)
one the flipside of this arguement, (I haven't watched the vid and am not going to till I'm back in the land of fast net), I remember EA's original F1 game for the PSX. I hit a corner so hard once that I flipped the car all the way over and landed back on my wheels. that was a game that flipping wasn't supposed to happen. almost locked the system up and I got some pretty crazy scenery mixing, but I DID flip her all the way over. (happened in slow-motion because it got 'stuck' upsidedown for a sec, lol)
peace,