In reply to tehmarks:
I was also there on Sunday, and saw some of the shenanigans. Little Tryfan was really busy - at least one team on most lines, lots of novices and people learning to lead...
The family initially soloed up to the large triangular niche about a third of the way up Crack 2, which was already occupied by a belayer. As we were leaving, Dad was 'helping' one of the children back down to the base of the crag by standing directly below the child (such that, if the child had slipped, they would have taken out Dad too).
Thought they might have got the hint that soloing below and around loads of roped climbers wasn’t the greatest of ideas, but clearly not if they later set off up Chimney Crack…