SJS, this is one of those rare times when we somewhat disagree, but only somewhat. In most cases, I am not in favor of potching. Sometimes (and the situation itself determines the proper course of action) it becomes necessary to utilize the hand to rear method. There is a reason Hashem padded it so well. But it is to be used sparingly, when no other option serves.
BTW, my 2 year old granddaughter is one of those rare angels who CAN be told not to draw on the walls or furniture and she will listen. We show her what she MAY use, and tell her that paper is for coloring, but walls are for staying clean. She has never colored on the walls, and if she accidentally gets some marker on her little table, she asks me for a baby wipe to clean it up when she is finished coloring.