Of course no one has had an issue with it, or they wouldn't be here. It's an odorless gas and gives off no warning. By the time you'd know you had a "problem" you'd be dead. Co scares the hell out of me! A guy I know had his own son die of it while sleeping in the cabin of a boat. Kid went into the berth to take a nap and never woke up. Call me crazy but I always have a Co alarm in my tent when I run the stove, and I have two in my trailer for the heater. Not taking any chances. I've never had an alarm go off but I sure have more peace of mind.