Pax as Cruise Autopilot
In Canada the regulations were amended to prohibit any non pilot touching the controls unless the PIC is an instructor. Before that I would put the right seat in charge of holding wings level and I would watch for traffic, talk to ATC, monitor the gauges and track, work out ETA (before GPS) and of course monitor "George" like a hawk after instructing. Took over approaching destination.
Pretty much the same for glider intros. After release, let them try out the controls and take back entering the circuit.
Do read the insurance policy.