But at least with lying or standing prone, there is some kind of feasible suspension of disbelief with the idea that the victim has been stunned and the likes of Lesnar and HHH can be believable in muscling their victim into position for the F5 or Pedigree.
With the Canadian Destroyer, the victim has to not only willingly participate in the move, but actively cause it. Petey Williams is doing nothing to make that move happen. He is in no position to make his opponent flip over backwards.
Have you ever seen someone able to do a forward flip with his back nearly at 90 degrees and his legs largely locked out?
And apart from the Rock taking a Stone Cold Stunner, has anyone ever been so stunned as to do a standing backflip onto their own head?