In the case of the paraglider pilot, the glider is suspended from the spreader bars - the coat-hanger style webbing that separates the pilot & passenger. If you look at those, they're not designed to take two carabiners because failure of the connection is just not a factor even though we saw it there with our own eyes.
The accident stats for PG nerds show that it's almost unheard of consequently, it isn't factored in to designs. On the point of the HG landing earlier, I think I was wrong about that. The passenger hanging off the left hand side of the base bar effectively prevents the pilot from weightshifting & therefore turning the glider toward the hill in the early stages of the flight. You can see that he pulls the bar in to descend the thing at a fair clip towards a landing so on reflection is doing his utmost to get back on the deck but as a retired PG & not an HG pilot, I bow to Neville's view of events.