Not mad, but smart! I remember this procedure was in our books, but was only to be done in extremly cold wx, ie -30 celsius-ish. Same with the nose wheel steering left right, and idle for several minutes to let the IDGs stabilize. And having the ground crew heating the engines before starting.
I believe the full flap exercise is to make sure the flaps are not frozen in any way, but for that very reason I would deice before trying to move them.
We taxi to and from deice with flaps up, and only set take off flaps right before lining up. This way we don't expose the untreated areas to icing conditions before we take off.