My memory of the video showed fiber spokes, attached to metal ends near the rim, I'm sure threaded with nipples; I'm sure they need that for truing the wheel. Those high-strength fiber lines like aramid and UHMWPE have the stiffness of steel and don't stretch a hair, so that truing job should be pretty stable. Although... when folded up, the spokes go loose, so the spoke nipples could easily move; They'd need a means to prevent that, maybe a small nut locked against the nipple on the inboard side.