Hang Glder Passenger Mayday Video
There are often times when hang glider instructor takes a passenger on a dual flight and there is a video of that now on the net.
It doesn't seem to be much challenge, with the BIG CAVEAT that since each person has his own harness and line you must make sure that both are clipped into the overhead spot where the tubes join.
The video shows either the instructor didn't clip the man in or his came undone, but shortly after takeoff he is dangling by only his left hand holding the bar. There are trees below so that have to clear a ways before being able to land on grass, but he holds on the whole time. Amazinly he goes back a year later and flies again for a duel flgith, this time with another company and no problem.