Are super flexible shafted clubs of any value in training? I knew an older golfer back when I was stationed at MCAS Cherry Point that would practice with a really whippy shafted three wood. Got my attention 'cause he would usually beat us young “flat bellies”, as the retirees used to call us. 
You mean like this?
[youtube]http://www.youtube.com/watch?v=Gsvg6SZUiJ4[/youtube]
The operative difference here is no pressure on the shaft, so good luck with that and hitting…but they are fun, and a blast to use, if one wants to pure swing. 
Makes sense. Thanks!
Great drill for swingers.
Horrible to even think about for hitters. 
Sorry for putting that mental picture out there…