cant always look behind u.....some of the hills that ive come back down have been so steep your almost vertical. but i agree with the avy course, first aid, def the gps lol, etc
I am by no means trying to start an arguement of anykind, but it takes less than 1 second to shoulder check. It starts out being a pain in the azz, but once you force yourself to do it for a weekend it will become a habbit. Keep in mind that the average person doesn't ride a boosted 174" sled, so coming down something so steep that you can't look back for a split second shouldn't be a problem
I've seen guys put a little convex mirror on their sled that they can look in on their way down to see if anything is coming up behind them.