the video is great and shows a lot of unhooked moves,

The bungee is not all that complex, it is not a special system for magical relaunch like a seperate tool, the purpose of the bungee is simple, as I understand, to keep the steering line under the kite by not letting the wing tip fold back when the kite flips over from being on its back,

Kites with Y 5th are harder to get to the edge of the window if they are on their back as the Y keeps it central, with the Rebel you simply had to hold the steering line (when on its back) and give it a little while to flip over, however sometimes the wing tip would fold back on itself and let the line roll over the back of the kite*, this modification simply forces the wingtip to fold inwards and therefore reduce the risk of twist, that what I think, I will certainly let you know once having tested it.

*Not unusual for SLE kite when in a mixed position on the water.

Dazza