The most interesting point for me in this and the previous thread, is that I don't recall any mention of this kind of issue in my training.
Common sense has always dictated to me that I don't exit the aircraft with the prop turning, and as I always accompany non-pilot pax at all times at a field, the issue of passengers near the prop has never been an issue (and I don't let them near it while they're watching me walk-around either).
However, hot changes (and not to do them) were never mentioned during my PPL training, other than the fact that the instructor leaves the aircraft whilst it's running to send students off on solo detail.
Could this leave the less aware new PPL's more open to making this kind of terrible mistake?