Agreed. I wouldn't let my life depend on the reliability of any mech or electronic device. I don't winter camp but I know some who do. They get top notch gear such as really good sleeping bag and tent, but don't use any heater. I am told that just a candle can heat such a small space quite a bit w/o the CO hazard. If you wanted to let it burn while you sleep you'd need to make very sure it couldn't tip and create a fire hazard, of course.