Frankly, I don't think anyone with just a modicum of outdoor experience will not have had a close call or two, or will not have been close to someone else's bad experience.

I would review pertinent examples, and point out where better preparations, filing a trip plan, checking the weather report, etc., would have resulted in a better outcome. Don't expect an immediate epiphany and instant agreement with your position, but the notion of better preps will sink in if they are even a tiny bit rational.

I remember when I was a young sprout, I ran across the annual publications of Accidents in American Mountaineering, published by the American Mountaineering Club. It gave me the notion that sooner or later it was going to be my turn in the barrel. in turn I started carrying emergency gear. And, yes, it paid off.