Years ago when I had friends and relatives with small children who came to visit, I would make a point of talking to the kids themselves, on their level, and explain to them what was expected of them and what the rules were. Meaning what was and what was not allowed. This prevented a lot of problems. Sometimes kids misbehave out of ignorance rather than malice. It is hard for them to respect the rules if they don't know what the rules are. On the very few occasions when there was a child that was out of control, I would simply tell the parents to take their darling home because I coud not guarantee his safety. I had the advantage because I did not care whether my relatives liked me or not. If they did fine, and if they didn't, that was OK too. I don't have this problem any more because the only relative I now have with children is a niece who thinks I am a savage because I raise and butcher my own meat chickens and wouldn't dream of setting foot on my property. I do what I can to make sure she does not change her opinion of me.