Dang right, that 6-12" drop will scare the crap out of you. I know it got my heart racing pretty dang good.
As far as the tubing, I am not sure why he is surprised about it. The amount of force was insanely great. Apparently more than the tensile strength of the aluminum with a hole drilled in it. One thing he should be really thankful for, is that summit used a double shear on their bolts and a decent bolt that bent and did not shear off.
As far as having the upper and lower tied together. I dont have them any longer than I can reach while nearly standing but my butt still sitting/touching the bar. If that lower falls, I dont want to have to use my upper body strength to hold myself, lower myself, hold myself while I'm trying to get my feet around the platform and then pick myself back up. I want a little weight to be held by my butt. I also tie the top end of the tether high on the stand so I can reach it while sitting on the bar, that way I dont have to use my feet for really anything but leveling the platform out when I reel it up by hand to get it clamped on the tree. It might make for short up and down motions but I would rather take 10 more moves to get up or down the same distance and not have to worry about my foot platform falling a great distance and not being able to retreive it.