I am commenting before watching the vid -- don't know if I want to.
I ALWAYS do a visual check on my lanyard clips when I switch from one to the other to get around a limb, or when I switch in or off my life line, in addition to "weighting" the new piece of protection.
Switching to my rescue 8 (a figure 8 with "horns"), same thing. I will loop the 8 on the life line, tie it off with a few wraps and a half hitch behind the horns, and gradually loosen a flip line until it is loose and unsnap it (with one hand gripping both pieces of rope above the 8); then I use the other hand to unbind the 8, and rappel.
Never had a problem, knock on wood (just knocked on my desk!
I HAVE noticed that one or two times my lanyard clip, clip (or 'biner) at the end of my lifeline or /biner on my split tail did not close because of a chunk of pitch or bark in it -- I even got a piece of a jacket in a clip once-- something that could go unseen without a visual check.
This is an ingrained habit, like double checking where the rigging and flip line is when cutting a piece.
Now if I could just transfer that focus to my life on the ground...:bang: