Now a question for the informed, could any other adult travelling on the same flight came forward and say that he would accompany the children?
Doubt it, CRB checks and all that for anyone involved with children (imagine the furor if a non-checked person had done the wrong thing!)
At the end of the day we have a situation where (supposedly) well educated and responsible people have arranged a trip for other people's children, not checked the T&C's of the carrier or relied on others to do it for them, are on the edge of compliance with national advice for supervision levels, I somehow doubt I would let any child of mine (he's 19 now so not an issue) travel abroad with that group of "responsible people".
Should add that I was involved with a volunteer youth organisation for 18 years starting from about 23 years ago, the 1:10 ratio was in force back then - though oddly enough lots of schools didn't comply with it!