I disagree Gregg. If you watch the rear-view mirror, the Golf stays behind up to the point of impact. The drastic change in lateral momentum come from the black BMW IMHO, who possibly slid thru the apex and made heavy contact. It's a similar feel to my in-car from MidO during my incident. Any contact from the VW to cause a spin would've been more of a push than a slam.
One bit of advice to the driver- if you'd have locked it down immediately, you wouldn't have had the second impact to your front end. I realize it's real easy to sit here and say that now, and I'm not sure if I'd have been able to do any better in-the-moment than you did, especially since the hit was unexpected.
Not sure if this vid was posted, but it does show the back end of the accordion. No good visual on this hit though.
[ame]http://www.youtube.com/watch?v=Ov2Bdf4iNHs[/ame]
Edit: Rick- where was the heaviest damage in the rear? If you watch, the VW goes to DR before impact. If the heavy damage is your rear bumper pushed in on the pass. side, it's from the VW (or a later hit). If you have heavy left rear corner impact damage, it was the BMW.
2nd edit: The video above does not show damage to the right rear correlating to a heavy impact from the VW. It was a hard lick, there would be damage. It *appears* that there is left rear quarter damage. If that's the case, it's the BMW all the way. The BMW's front end damage should match, and from his retirement, I'd say it does. Forensic analysis says BMW.