My friend has three kids close in age, the eldest being 12- two boys and a girl. I suppose the girl is quite mature really, despite being the youngest, as she is already used to cooking for the entire family.
Anyway, my friend packed them off to their aunt and uncle for a fortnight last summer, only to discover that there had been practically zero adult supervision, and that the children had actually been allowed to go camping all on their own 
Apparently this was alright because the ten year old cousin they went with is handy with a pocket-knife and can climb like a monkey
...oh, and they took the family dog with them, who is very protective.
AIBU to be horrified? God only knows what sort of scrapes they could have got into. Friend genuinely doesn't seem bothered, btw, and reckons she'll probably let them spend part of the Easter hols with this family again 