One general tool to protect innocent people from accidents caused by pilots is the PASSENGER BRIEFING.
This step can often be found on the "before engine start" checklists and verbalizing the task to be flown reduces the likelyhood of doing something stupid, like unauthorized manouvers, going into IMC with no rating/currency for that etc.
Moreover, the passenger (pilot-rated or not) can also point out deviations that compromise safety and can feel when the flight becomes somewhat abnormal, requesting a return to what was originally planned, or a return to base.
Every non-flying pilot and passenger has the right for a briefing before engine start.
I wouldn't fly with anyone who doesn't give me a brief plan (or plans, e.g., alternatives) before engine start. That's valid also when I fly with instructors too. I need to know, and I have the right to know. You don't play along? You fly alone, or with some other poor soul, have a nice day, bye
A good side-effect is that briefed passengers tolerate turbulence better, indicate any motion-sickness earlier, cooperate with the pilot-flying much better (eg.., scanning for traffic).
So if it's missing totally.... it's a huge red warning light in my head that it's time to step out of that aircraft and live another day.