distracted wrote:And I can't see why the decision from #5 is different from #4
The obvious difference being that in the case of 4, some competitors have gained an advantage due to breaking the rules, but can't reasonably be disqualified because the map was incorrect. Being disadvantaged due to an incorrect map is a subtly different issue (I think the numbers involved also has an influence - were it not for so many being affected, personally I'd be tempted to just disqualify those in case 4).
the organiser should have been aware that #8 was a possibility and mitigated
Lots of things are a possibility - the question is which ones are a reasonable probability. Insufficient information to judge whether that was the case here - otherwise we come back to having to individually police all controls in the forest to ensure they're not disturbed.