In America we have become accustomed to guard rails everywhere, and signs announcing the smallest hazards. This is OK so far as it goes, but perhaps it makes us a bit soft. Here we read about a tree swing that fell down when a full grown man used it. At least 90% [1] of tree swings in America are built without professional engineering or even inspection.
I'm not apologizing for the host in this case, but I do think that some people are open to living in a world where not every conceivable danger has been mitigated. The hard part is finding anyone so willing once a freak accident happens to them.
[1] I'm lowballing this estimate so much that it should be obviously true to anyone who grew up in the non-urban US.