Nice work. I have continuously knocked mine off with the starter handle as well definitely not the best location for it. I am about in the habit of just holding on to the handle until it is all the way back in now.
On another note I have noticed everyone wearing these attached to the D ring of their gear but twice already this year I have been in situations where the sled rolled and I was stuck close enough to it that the tether didn't pull but really couldn't get to the kill button because of where I was stuck. I have started wearing the tether looped around my right wrist and find it nice to be able to pull that thing off when I need to. I guess I could probably have reached down and pulled it off my gear as well but just something to think about. I have also heard a lot of my riding group complaining about popping theirs off moving from side to side when it was on their gear. I have yet to pop mine off a single time on accident with it on my right wrist.