All of my cages are made from flame retardant material, so even if my heat tape were to malfunction there isn't anything that could hold a flame. My cages could melt and my reptiles could die but my house won't burn down. I use herpstat 4's 1 channel per heat source. No exceptions. In my opinion this is the biggest risk that people in this hobby take.
So between the safety features in my herpstat and the fact that my cages won't hold a flame I sleep well at night, but you can never be too careful.