Yeah, my theory is that you can get away with it most of the time, but with firm snow and solid traction the track can't spin when you land so all that inertia yanks the rear of the skid up and forward with much greater force than usual. When combined with the weight of the sled coming down something has to give. Usually see broken limiter straps and bent tension rods with the rear shock pushing the pivot over. Oh yeah, bent rails too.