Safety is sometimes a serious affair. The elder at left seems somewhat straight minded . Instead of negociating with the big girl, he will prefer to leash both child to get peace of mind and avoid any kind of bolstering. From modern psychology viewpoint, this kind of behavior is obsolete. But from any traditionalists in USA, the leash can be synonymous of "Fther knows best" or "It's a mom decision". I just think that the girl is surely resenting inside her mind.