If you use your brakes it shouldn't be a problem. I've ran a suicide hub on my beater for a year now with no issues. When I first set it up I didn't put the cog on tight enough and it slipped once after skidding. Nothing happened, but if I had been unlucky I could've lost some teeth. Rotafix the cog on, then power around on some hills for a couple days, then cinch down a BB lockring as tight as it will go. After that it shouldn't move again, even with backpressure, but I recommend using your brakes for stopping and use backpedaling just to manage speed.