Suck less at Golf with the D2 Swing Trainer

The D2 Swing Trainer, unlike the only other golf swing fixer gadget I've ever seen, was not a flimsy contraption involving dangling weights and sticks. By cleverly weighting an otherwise normal-looking club, it makes it hard to backswing incorrectly, promoting good form and accurate shots. Its heavy yellow head also looks useful should an on-green business meeting go awry and personal combat becomes unavoidable.

Though I saw it in action yesterday (in a friend's kitchen!), I can't vouch for it, as I don't play golf. My experience of the game is limited to 2 rounds of pitch and putt, neither of which was survived by the golf club at hand.
 
Here's some video from one of the various websites advertising it — the official one is at D2golfbetter. It costs $100.