[Yoda]

V-E-R-Y important clip!

Wouldn't you say that over-swiveling (based on the false idea that it would smack the ball harder) is more common than under-swiveling?

In most cases, there is NO Finish Swivel. And that is a chief reason why so many play so poorly.

However, once the player begins in earnest to incorporate into his Stroke this missing element, then, as you have said, it is easy to make the mistake of executing Impact as a Swivel Action (and not as a Hinge Action). I should know, because before The Golfing Machine, I did it for years. You must Hinge first, and only then Swivel. Or else expect a mass exodus of the left rough field mice every time you step to the Tee.

Bobby Jones once wrote:

"There is no virtue that cannot be exaggerated into a fault."

Certainly, that truth applies to the Finish Swivel.