As a fire fighter I have seen many burned decks and homes caused by people cooking on charcoal grills on wood decks. many times the first that the homeowner knows about it is when the fire trucks pull up in front of their house at 3 AM. A small diplaced coal would smolder for a few hours and then light off burning up the deck and the back of the house. A passer by would be the one calling in the fire. Often smoke detectors will not alarm because the fire is on the outside of the house. I have even seen where a large fire was in the attic, caused by a charcoal grill on the deck. The fire started on the deck, went up through the vented soffit and into the attic. There was very significant damage. I say all that to say this, I do not grill with my WSM on my deck. The risk, for me and my family, is just to great for for the little bit of connivence it offers.