Consider this option. You throw two pork butts into the smoker the night before the big barbecue when your friends are coming over to eat, drink, and party. You go to bed with smoke billowing from your Cookshack as many of us have so often done.
During the evening your neighbor doesn't close his garbage can lid (a rarity itself), and a piece of paper blows from his garbage and, of all things, lands right on top of your smoker's exhaust hole. The wind suddenly dies allowing the paper to sit over the smoker's exhaust hole for a long period, and the paper eventually ignites. Just at that moment the wind strangely picks up again but ironically reverses direction causing the lit paper to blow back into your neighbor's yard. A rare updraft causes the lit paper to rise up and land right on top of his 20 year old cedar shake roof, ignites the shake roof and burns his house down. Fortunately, he and his family escape safely but unfortunately his pet Gerbil dies in the fire. It's a small "chance", but it can happen.
The only sensible thing to do is not to use your smoker overnight with no one attending it. Alternately, you could set up revolving 2 hour "smoker watches" with family members much like the cowboys did guarding the wagon trains from Indians. But instead of using rifles your sentinels can sit watch with garden hoses at the ready.