They're not free to rotate. If they were... *shudder*
There's a lot of technical information floating around, and a lot of people believe it to be true.
To give an analogy of sorts, go look at the IAAPA photos here on Coasterbuzz of Setpoint's Seizmic. First, imagine Arrow track instead of the box. Second, lower the seats so they're sort of centered with the track. Last, try to envision the seats spinning at a controlled rate by a third (?) rail.
It's been a while since I watched the video, and I didn't save it. Sorry. Somebody else want to comment on my description? How close was it?
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How dare you vanquish the Steel Phantom without his consent? Fear the Phantom's Revenge.