Neat video, and kinda makes me think more like not using the new hd snap ups. I was noticing on mine that when I put them on temporarily, they both seemed to want to just fall down, no over center at all. One moves easily, the other is a bit stiffer. BUT, the older style that I have used for years, have a very definite over center so the chains are only pulling down. I also wonder how much force is applied to that pin. I find it hard to believe that it would be able to hold up to a huge amount of side force. But then, the weak frames that we both are dealing with would probably fail first!!
Still, I feel that the older style may have less undesirable forces due to its more inside positioning of the hook. Just my .02 worth!!!