While i can agree with both sides, including the human error issues, I never set up anything gas over 30cc without an opto kill switch. For about USD 20 why leave it out? Even if you are the best, most careful guy out there i still recomend using one. the simple reason being that when there is a loss of Rx battery power it automatically kills the ignition. Can you imagine a 50cc or bigger plane that rockets out of control full throttle into fellow pilots or spectators......

Yeah i know you must check and recheck your Rx batteries and power setup BUT things happen, IF it ever does to me i have peace of mind at least my engine will cut too.

I know soemone who lost a 30% with DL50 on the front. Lost rx battery power, it flew full throttle into a chicken shed across the farm. TotalledEVERYTHING even the DL50was in about 15 pieces. With an opto kill it wouldnt even have reached the chicken shed. Imagine it had hit some of the workers......................

that said i never wear a seat belt while driving..................never drive over the speed limit either ....................