They would certainly know what to do about a stranger and the others, whilst being upsetting for a minute or two, would they actually have been dangerous?
They were never more than 5 mins away from home. I'm not justifying it, just explaining why it seemed OK to me at the time. I'd like to hear other views though.
I have been having some challenges with DS1's behaviour recently, but find he responds well to being given some responsibility, which is why I allowed them to go.