Been "observing" again

This time it's the performance of Uraken-Uchi.....
So I've been wondering what the current view in delivery of Uraken is with respect to the wrist movement or perhaps the lack of it.....
I was taught - many moons ago - that Uraken-Uchi was delivered using a snapping action using firstly the forearm/elbow snap action which then culminates in a further snapping action of the backfist/wrist joint- thus maximising the percussive impact and minimising the contact area of the strike......
My observations recently seem to induicate that most folk seem now to simply snap the elbow/forearm but keep the wrist "solid"

So what goes - ? new thinking or lazy students or poor instruction ?
